A hybrid conjugated polymer is presented that supports spike-timing-dependent plasticity (STDP) for neuromorphic computing devices while enabling environmental sustainability through biodegradability. The polymer, distinguished by its carbazole backbone and electrically responsive pendant carbazole groups, forms a two-terminal device that exhibits analog STDP behavior. Demonstrations focus on fundamental switching characteristics using individual devices, offering insights relevant to temporal learning tasks such as speech and image recognition. The energy cost per programming event is 60 nJ. Biodegradation is demonstrated using Pseudomonas resinovorans CA10 lysate, supporting reduced electronic waste. This work introduces a sustainable soft-matter platform for synaptic device development.

This study investigates the photophysical properties of halogenated benzylidene hydrazineyl–4-trifluoromethyl thiazole derivatives using combined experimental and computational methods. Structures were confirmed by NMR, IR, and high-resolution mass spectrometry (HRMS). Variation of halogen substituents (Cl, Br, I) enabled evaluation of substituent effects on electronic structure and excited-state behavior. Absorption and fluorescence measurements in dimethyl sulfoxide (DMSO) revealed efficient intramolecular charge transfer (ICT), driven by the electron-withdrawing trifluoromethyl group and conjugated hydrazone bridge. The 4bromo-2-hydroxy substituted derivative (3b) additionally shows features consistent with excited-state intramolecular proton transfer (ESIPT). Computational analysis supported these findings by elucidating frontier orbitals and charge distribution. Notably, despite the presence of heavy atoms and calculated spin-orbit coupled states, no significant population transfer to the triplet manifold was observed neither experimentally nor in simulations. These results demonstrate that how halogenation and electron-withdrawing substitution are effective strategies for tuning the excited-state dynamics of thiazole-based chromophores.

This work combines experimental and theoretical approaches to examine how the length of an alkyl linker can be used to tune the electrochemical, optical, and device-related electrical properties of carbazolylalkyl-substituted polydithienopyrrole polymers (pCxDTP). Using a scalable four-step synthetic route, a series of monomers with systematically varied alkyl spacers was prepared and subsequently electropolymerized directly onto conductive substrates, yielding uniform polymer films suitable for device integration. The polymer band gap ranges from to 2.4 for pC3DTP to 2.0 eV for pC12DTP. This trend arises from the concurrent increase of the HOMO and lowering of the LUMO levels, with both effects depending on the alkyl chain length. Sandwich devices with an ITO | pCxDTP | Al architecture show reproducible memristive behavior, characterized by pinched hysteresis loops and pronounced frequency dependence. Longer alkyl linkers result in a more pronounced hysteresis in currentvoltage already at higher sweep rates, revealing a clear relationship between molecular structure and device performance. Density functional theory and time-dependent DFT calculations are consistent with the experimental findings and indicate that alkyl linker length subtly influences frontier orbital energies, ionization potentials, and charge delocalization. Oligomer-level modeling further accounts for the observed band gap narrowing and spectral broadening through increased conjugation length and chain dispersity. Overall, these results highlight alkyl linker engineering as a practical strategy for optimizing conjugated polymers for electrochromic and memristive applications.

Compact models of memristors are essential for simulating large-scale neuromorphic systems, yet they often do not include description of complex dynamics like volatile relaxation and synaptic plasticity. We introduce a modular, computationally efficient memristor model that bridges this gap by integrating principles from physics and computational neuroscience. The model defines a framework consisting of a standard formulation of memristive device dynamics, a functional rule mapping state variables to cumulative conductance, a volatility module inspired by the theory of linear viscoelasticity and a saturation module implementing a linear-nonlinear technique. Additionally, we develop a formulation of synaptic-like plasticity inspired by a biological spike-timing-dependent plasticity (STDP) rule, which is compatible with the general framework for memristive devices. Finally, we propose a Laplace transform-based technique to derive the precise form of the mapping from state variables to cumulative conductance, replacing ad hoc voltage-current relationships with principled construction. We quantitatively validate the complete model against a rich set of experimental data from polymeric memristors exhibiting potentiation, synaptic-like plasticity and volatile decay. Our work presents a new paradigm for memristor modeling that is both practical for large-scale simulation and rich in explanatory power, providing a principled tool for the design of next-generation neuromorphic hardware.

Polymer–nanoparticle composites offer a versatile platform for tuning structure–property relationships in functional thin films. Poly(acrylic acid)-coated manganese(II) oxide nanoparticles (MnO@PAA) were incorporated into poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) to fabricate nanostructured thin films by dip-coating. Small-angle X-ray scattering and infrared spectroscopy indicate nanoparticle incorporation into block copolymer micelles via P4VP–PAA hydrogen bonding. Structural organization was investigated by X-ray reflectivity, transmission electron microscopy, grazing-incidence small-angle X-ray scattering, and broadband dielectric spectroscopy. Incorporating 2 wt% MnO@PAA preserved the hexagonal morphology and increased the interdomain spacing from 47.3 ± 0.1 to 54.2 ± 0.2 nm, while the film thickness increased from 27.2 ± 0.1 to 28.1 ± 0.1 nm. The average domain size increased from 13.2 ± 3.0 nm at 2 wt% to heterogeneous domains of 20–60 nm at 10 wt%, indicating aggregation-induced disorder. Moderate MnO loading (2–5 wt%) increased the dielectric permittivity from 2.72 ± 0.1 for neat PS-b-P4VP to 2.90 ± 0.1 for the 5 wt% composite through enhanced Maxwell–Wagner–Sillars polarization, whereas 10 wt% loading reduced the beneficial interfacial polarization due to nanoparticle aggregation. These findings demonstrate how nanoparticle-polymer interactions influence nanoscale organization and functional dielectric response, providing design guidelines for nanostructured dielectric polymer thin films.

We present hydrothermal synthesis and comprehensive physicochemical characterization of water-soluble Ag2S quantum dots (QDs) emitting in the second near-infrared biological window (NIR-II), stabilized by chiral ligands: l- and d-penicillamine (Pen). By systematically optimizing reaction temperature, time, and the Ag : S ratio, we significantly improved the photophysical properties of the QDs. The obtained Ag2S/Pen QDs exhibited NIR-II emission (lambda EM. similar to 1040 nm) with a fair quantum yield (QY = 1.1%), high colloidal stability, low cytotoxicity, and fluorescence lifetime reaching 84 ns in aqueous media. The use of enantiomerically pure and racemic variants of Pen allowed us to investigate the influence of stereoisomer configuration on morphology and consequently, linear and nonlinear optical (NLO) properties of the QDs. Spectrally-resolved NLO study using a femtosecond laser Z-scan technique showed the presence of two-photon absorption (2PA) with a peak cross section reaching sigma 2 similar to 511 GM (Goeppert-Mayer units) for Ag2S/d-Pen excited at lambda EXC. = 824 nm and 260 GM (lambda EXC. = 950 nm) for Ag2S/l-Pen, respectively. Biocompatibility studies in THP-1 macrophages and HLMEC endothelial cells revealed favorable tolerance profiles for Ag2S/Pen QDs, particularly in immune cells. Notably, macrophages maintained high viability and even showed enhanced metabolic activity, while endothelial cells exhibited good tolerance at lower concentrations, supporting the potential of these QDs for biomedical applications involving immune and vascular systems. These findings demonstrate that the structure of surface ligands plays a key role in controlling the structural and optical properties of Ag2S QDs, providing insights for the design of NIR fluorescent nanomaterials for biomedical and photonic applications.

In this study, we present a new synthetic approach to obtain trimethoxysilylazachalcones, a family of donor-acceptor chromophores exhibiting strong intramolecular charge-transfer behavior. Their distinct optical features, validated through comprehensive spectroscopic analysis and theoretical modeling, make them promising candidates for advanced functional applications. To harness and further enhance their photophysical potential, the chromophores were covalently anchored onto plasmonic gold nanoshells (NSs), forming hybrid nanostructures engineered for enhancing excited state processes through plasmon-molecule interactions. Femtosecond transient absorption spectroscopy revealed pronounced differences in the excited-state dynamics between the free and hybrid systems. While several plasmon-related processes, such as local electromagnetic-field enhancement, hot-electron transfer to the molecular LUMO, and the suppression of non-radiative decay through restricted molecular mobility and strong interfacial electronic coupling-are possible, we believe that the dominant contribution in our measurements arises from nanoparticle heating and its resulting thermal response. The results underscore the potential of such plasmon-enhanced hybrid materials in technologies where control over excited-state dynamics is essential. Applications span photonic devices, optical sensors, and light-triggered biomedical tools such as photodynamic therapy and high-resolution bioimaging, where prolonged excited-state lifetimes can directly translate into improved functionality and sensitivity.

By analyzing previously reported transient absorption spectra of thin films of diketopyrrolopyrroles carrying n-hexyl, n-butyl, or 2-(adamant-1-yl)ethyl substituents, we found that the efficient singlet fission is accompanied by small but observable oscillations on the ps time scale. Specifically, clearly resolved vibrational oscillations with a period of 1.6 ps were observed in the time course of the transient absorption of thin films of N,N'-di-n-butyl-2,5-dihydro-3,6-bis-2-thienylpyrrolo[3,4-c]pyrrole-1,4-dione prepared by spin-casting, with a singlet fission yield approaching 160%. Here we show that these oscillations are formed by a population exchange between singlet and triplet-pair excitations, which is controlled by the inter-molecular vibrations of adjacent molecules in a centrosymmetric crystal configuration. Due to a very broad spectral distribution of these low-frequency vibrational modes developed after the photoexcitation, the probability of the conical intersection of the potential energy surfaces related to singlet and triplet-pair states is efficiently increased. The singlet and triplet states population exchange facilitated by coherently excited vibrations near the conical intersection also changes the transition dipole moments seen in the optical time-resolved pump-probe experiment. It was shown that these oscillations decay within the initial ca. 10 ps after photoexcitation, while on a timescale of 90 ps, the transient spectra gradually evolve into a long-lived component, formed exclusively by the triplet states.

The memristive behaviour of metallosupramolecular polymer, formed by coordination self-assembly of a ditopic 9,10-bis(tpy)anthracene ligand with Co 2+ salts, depends on the nature of counterions, with acetate ions demonstrating the best memory effect.

The rheology of conductive polymer composites has attracted much attention due to the high sensitivity of this method to investigate the formation of conductive particle structures. In this contribution, we evaluated the effect of two specific procedures for the preparation of the single-wall carbon nanotube-filled nanocomposites in terms of their concentration and the quality of the dispersion in the high-density polyethylene matrix. In particular, we focused on the influence of the promising non-covalent modification process using alkylated pyrene resulting in good dispersion in nonpolar environments. It was proved that the properties of the nanocomposites were controlled by the modification procedure used. The results obtained proved better dispersion and higher mobility of conductive nanoparticles in the case of the simpler modification procedure used. In addition, the rheological and electrical measurements before and after isothermal annealing in the molten state showed further conductivity increase. This approach allowed us to investigate the formation of conductive structures in a comprehensive manner. The high sensitivity of the measurements in the oscillatory shear flow to the changes in composite microstructure confirms their benefits for probing the conductive structure formation.

The aggregation behavior of π-conjugated molecules critically influences their excited-state dynamics and thus their performance in optoelectronic applications [...]

The synthesis and characterization of a series of carbazole-based polymers are investigated, focusing on their potential application in artificial intelligence (AI)-driven bistable memory devices and neuromorphic computing architectures [...]

Organic semiconductors (OSCs) have emerged as promising materials for next-generation optoelectronic devices owing to their cost-effective processing and mechanical flexibility. Nevertheless, a thorough comprehension of ultrafast phenomena responsible for charge generation, transport, and recombination is imperative to fully exploit their potential. In this paper, we employ time-resolved spectroscopic ellipsometry (TRSE), an ultrafast, surface-sensitive, and non-invasive method, to explore these processes in thin films of a thiophene-linked diketopyrrolopyrrole (TDPP) derivative. While TRSE has proven effective for inorganic semiconductors, its application to organic materials remains unexplored. This technique is a crucial solution for measuring opaque samples or layers deposited on non-transparent substrates. TDPP molecule was selected for the measurement due to extensive research on this class of organic dyes using alternative spectroscopic techniques. After synthesis of TDPP via a multistep Suzuki-Miyaura cross coupling reaction, its thin film was deposited via vacuum sublimation. We demonstrate here the TRSE’s capability to elucidate optical phenomena in this material on a picosecond timescale, quantify the impacts of radiation damage, and derive kinetics without discernible sample damage. To support our findings, we measured kinetics using transient absorption spectroscopy (TAS) and validated the results. These findings highlight TRSE’s potential in understanding behaviors in organic materials and advancing their photophysics paving the way for better knowledge-based design and optimization of OSC-based devices.

Synapse is a connection between two neurons (or a sensory cell and a neuron) used to transmit excitations. Memristors designed for neuromorphic applications must exhibit reliable analog characteristics, in particular, a switching transition with a continuously variable resistance state and a predictable response. These properties are required in order for the memristor to be used in devices for the construction of physical autonomous artificial neural networks that are independent of programming by other external software means. Synaptic plasticity (SP) is central to Hebbian learning. SP can be divided into a short-term (STP), and long-term plasticity (LTP). 1 Both are important for the functioning of the human brain. Fundamental characteristics of the functioning of neuronal synapses in nervous systems include spike-timing dependent plasticity (STDP), whose emulation in an artificial device is critical for simulating biological systems. According to Hebb's rule, a synapse increases its efficiency if it is consistently involved in firing a postsynaptic target neuron. Similar functionality can be achieved on thin films of ditopic π-conjugated bis-terpyridine (tpy-) ligands that form supramolecular structures, in which the ligands are interconnected by complexation with metal ions. These molecules offer a low energy operation with improved reproducibility of memristive characteristics. They possess low-lying molecular energy levels and relatively narrow bandgap enabling the low-power consuming resistive switching and longer stability. We used a bis-terpyridine ligands based on 9-phenyl carbazole, Cbz, and its complex with cobalt Co 2+ ions as an active layer of a memristor device. A two-terminal memristor architecture was employed, consisting of the ligand or its cobalt complex deposited on an ITO substrate, and aluminum, gold, or gallium as a top electrode. The Cbz molecule, when deposited in a form of thin film by vacuum sublimation, exhibits an excellent nonvolatile bistable memory behavior, while Co-Cbz exhibits both electronic memory and synaptic plasticity, depending on the amplitude of applied voltage.. The cobalt complex displayed a synaptic effect characterized by subsequent potentiation and depression cycles. 2 To measure spike timing-dependent plasticity (STDP), an electrical circuit was employed with the measured element connected in a test setup to pulse generator. Measurements was performed by sending a presynaptic excitation (electrical pulse) at time t = 0 and then sending a postsynaptic excitation at time Dt. This was followed by a weak electrical pulse to measure conductivity. Voltage-induced modulation of synaptic weight was observed with a low applied voltage below 500 mV and short pulse duration below 20 ms. Pair pulse facilitation and pair pulse depression demonstrated significant synaptic weight changes, showing the cobalt complex ability to emulate biological neurons. The polymer structure is shown in the Figure, together with the examples of its STP and LTP. The figure shows the ability to mimic the paired-pulse facilitation and depression. The time courses of the read current decay after the subtraction of the current in equilibrium, without excitation, shown also in the Figure, could be fitted by a stretched exponential function, There are two processes clearly distinguished, running in different timescales, the slower one extended to thousands of seconds. It shows that the diffusion of counter ions participates on the mechanism. The operational mechanism of this memristor was attributed to a combination of the redox effect in the ligand and complex, and to the voltage induced migration of perchlorate counter ions, and subsequent redox processes, altering the metal-to ligand charge transfer band and changing the conducting state of the active layer. Acknowledgments: The work was financially supported by the MEYS of the Czech Republic, project LUAUS24032 References Chang, T., Jo, S. H. & Lu, W.: Short-term memory to long-term memory transition in a nanoscale memristor. ACS Nano 5 , 7669–7676 (2011). Pandey, A., Chernyshev, A., Panthi, Y.R., Zedník, J., Šturcová, A., Konefal, M., Kočková, O., Foulger, S.H., Vohlídal, J., and Pfleger, J.: Synapse-Mimicking Memristors Based on 3,6-Di(tpy)-9-Phenylcarbazole Unimer and Its Copolymer with Cobalt(II) Ions. Polymers 2024; 16. Figure 1

To effectively combat advanced cancers, next-generation nanomedicines should combine both therapeutic and diagnostic functions. In this study, we developed stimulus-responsive theranostics systems based on micellar nanostructures that deliver derivatives of tetraphenylporphyrins (TPP) bound via tumor microenvironment-sensitive hydrazone bonds. These nanomedicines are engineered using a micelle-forming polymer-TPP conjugate, enabling the pH-sensitive activation of both photodynamic therapy (PDT) and fluorescence. Two pH-sensitive and one stable polymer-TPP conjugates were synthesized and characterized by size exclusion chromatography and TPP release rates. Micelle stability was evaluated using UV/vis spectroscopy, while fluorescence and singlet oxygen production were measured to determine their theranostics potential. Femtosecond transient absorption and time-correlated single photon counting techniques were employed for the photophysical evaluation of micellar systems. Compared to polymer conjugates where TPP is linked through nondegradable amide bonds, the pH-sensitive systems exhibit superior physicochemical properties. These micellar conjugates are highly stable, allowing prolonged circulation in the body while remaining in an "off" state, where fluorescence and singlet oxygen production are minimized. Overall, the hydrazone-linked conjugates display favorable properties that make them strong candidates for future anticancer theranostic applications.

This study presents a comparative investigation of ultrafast photophysical processes in thin films of eosin Y (EY) and palladium (II) octaethylporphyrin (PdOEP) as triplet sensitizers, combined with bis(terpyridine-4′-yl)terthiophene (T) as an annihilator [...]

Since the introduction of a concept of memristor by Leon Chua in 1971 as the fourth fundamental passive component in electronic circuits, and its functional prototype introduced by HP Lab in 2008, research has increasingly concentrated on exploring its application ability in electronic circuits. First, the memristor principles have been exploited in various memory devices within a classical von Neumann computer architecture. The properties of memristor were found particularly suitable for resistive random-access memories (ReRAM). 1 Contrary to the classical von Neumann architecture based on the binary logic, advanced methods like neuromorphic computing require an electronic element with continuously varying states depending on previous input signals. The input signal consists of a sequence of voltage spikes that stimulate the device, similarly as a neural synapse does in biological systems. These trains of spikes change the output state of the device continuously to a lower resistance state, mimicking a learning process. Having these functionalities, memristors are considered to be possible building blocks of brain-inspired neuromorphic computing and artificial neural networks. 2 Memristors with neurosynaptic functionality take a continuity of resistance values with synaptic weights modulated by the number and frequency of homogeneous spikes. In order to mimic the neural synapse, memristors must exhibit analog properties including non-abrupt switching transitions, memory loss, continuously variable resistance states, and predictable response. We present such functionality on thin films of two kinds of organic materials: (i) A newly synthesized poly(methacrylamide) derivative with carbazole charge transporting group separated from the polymer backbone by an alkyl chain, was synthesized recently and found to behave as a bistable resistive memory. 3 Thin films of the polymer, sandwiched between Al and ITO electrodes, exhibit rewritable flash memory behavior with bistable conductivity, with the set switching voltage ranging from 2 to 4.5 V, and the current ON/OFF ratio exceeding 100. The device demonstrates a remarkable lifetime and remains persistent for more than 10 4 seconds under the static voltage of 0.5 V. The main physical mechanisms driving the resistive switching have been attributed to the electric field-induced reorientation of heterocycles, which modulates charge transport, and trapping/detrapping of charges in localized states within the bulk of the polymer. Memory persistence is strengthened by the physical crosslinking caused by hydrogen bonds between amide and carbonyl groups in the side chains. Depending on the layer thickness, electrode material and applied voltage range the electrical characteristics can change from bistable to analog behavior showing memristive properties. (ii) Ditopic π-conjugated bis-terpyridine (tpy-) ligands form supramolecular structures in which the ligands are interconnected by complexation with metal ions. These molecules offer a low energy operation with improved reproducibility of memristive characteristics. They possess low-lying molecular energy levels and relatively narrow bandgap enabling the low-power consuming resistive switching and longer stability. We used a newly synthesized bis-terpyridine ligands based on 9-phenyl carbazole, Cbz, and its complex with cobalt Co 2+ as an active layer of a memristor device. A two-terminal memristor architecture was employed, consisting of the ligand or its cobalt complex deposited on an ITO substrate, and aluminum, gold, or gallium as a top electrode. We show that Cbz as a memristor active layer exhibits an excellent nonvolatile bistable memory behavior, while Co-Cbz exhibits both electronic memory and synaptic plasticity. The ligand exhibited bi-stable conduction and non-volatile memory effect with persistence over 18 hours, while its cobalt complex displayed a synaptic effect characterized by subsequent potentiation and depression cycles. Voltage-induced modulation of synaptic weight was observed with a low applied voltage below 500 mV and short pulse duration below 20 ms. Pair pulse facilitation and pair pulse depression demonstrated significant synaptic weight changes, showing the cobalt complex ability to emulate biological neurons. The operational mechanism was attributed to a combination of the redox effect in the ligand and complex, and to the voltage-induced migration of perchlorate counter ions and subsequent redox processes, altering the metal-to-ligand charge transfer band and changing the conducting state of the active layer. Acknowledgments: The work was financially supported by the Czech Science Foundation, project 24-10384S, and MEYS of the Czech Republic, project LUAUS24032. Strukov, D. B., Snider, G. S., Stewart, D. R. & Williams, R. S. The missing memristor found. Nature 453 , 80–83 (2008). Chang, T., Jo, S. H. & Lu, W. Short-term memory to long-term memory transition in a nanoscale memristor. ACS Nano 5 , 7669–7676 (2011). Panthi, Y.R, Pfleger, J., Vyprachticky, D., Pandey, A., Thottappali, M.A., Sedenkova, I., Konefal, M. & Foulger, S.H. Rewritable resistive memory effect in poly[N-(3-(9H-carbazol-9-yl)propyl)-methacrylamide] memristor. Mater. Chem. C 11 , 17093 (2023).

Graphene oxide (GO) exhibits very poor photoluminescence (PL) characteristics because of the nonradiative recombination of electron-hole pairs. One of the crucial approaches for the enhancement of the optical features of GO is functionalization. In this study, we present a novel catalyst-free, rapid, one-step, aqueous-phase synthetic approach using SELECTFLUOR under mild conditions that provide access to highly photoluminescent fluorinated graphene oxide (FGO) emitting in the visible region. Time-resolved fluorescence spectroscopy and femtosecond transient absorption spectroscopy revealed that the enhanced PL is due to the increased pi* -> pi transition and weaker electron-phonon interactions in FGO. Most importantly, the structure and composition analyses using F-19 NMR and X-ray photoelectron spectroscopy suggest that the C-F bond on the basal plane neighboring to the aromatic rings is the key factor behind the enhancement of the fluorescence of FGO. Identification of the underlying C-F bonding features behind the emergence of strong orange fluorescence will contribute immensely to the fundamental understanding of the structure and optical property relationship of FGO. Moreover, strong orange fluorescence remains stable in a solid thin film of FGO, which offers a unique solution-processable route toward the integration of FGO in solid-state optoelectronic devices.

The title compound, unimer U (tpy stands for 2,2′:6′,2″-terpyridin-4′-yl end-group), by itself shows the memristor effect with a retention time of 18 h and persistence of 11 h. Its coordination copolymer with Co(II) ions, [CoU]n, exhibits multimodal resistance changes similar to the synaptic responses observed in biological systems. More than 320 cycles of potentiation and depression measured in continuous sequence occurred without observing a significant current change, confirming the operational stability and reproducibility of the device based on the [CoU]n polymer. The synaptic effect of a device with an indium tin oxide (ITO)/[CoU]n/top-electrode (TE) configuration is more pronounced for the device with TE = Au compared to devices with TE = Al or Ga. However, the latter TEs provide a cost-effective approach without any significant compromise in device plasticity. The detected changes in the synaptic weight, about 12% for pair-pulse facilitation and 80% for its depression, together with a millisecond trigger and reading pulses that decay exponentially on the time scale typical of neurosynapses, justify the device’s ability to learn and memorize. These properties offer potential applications in neuromorphic computation and brain-inspired synaptic devices.

Diketopyrrolopyrrole (DPP) functionalised with electron donating unit act as donor-acceptor molecules that have shown potential for dye application and photovoltaics. These molecules offer broad absorption/emission properties and structure-dependent dynamics. We utilised femtosecond pump-probe spectroscopy, to study the photo-initiated dynamics of thiophene linked DPP derivatives. The thio-DPPs are further functionalised by different electrons withdrawing terminal groups: benzoxazole and thiophene dicyanide. The strongly emissive benzoxazole derivative (chloroform solution) directly relaxes to the ground singlet state. Thiophene dicyanide derivative exhibit distinct spectral evolution in the first 10 ps associated with structural and vibronic process. Later it crosses over to the triplet state with a large yield (20%). In the solid-state thin film, we observed signal that reminiscences singlet fission. However, upon careful analysis of temperature-dependent steady state absorbance spectra, we conclude that these features are due to laser-induced thermal artefacts. We describe a simplified excited state evolution in the thin film which is devoid of any additional excited state. These findings bear significant implications for the analysis of triplet formation, which plays a major role in the photophysics of many organic materials.