Organic photodetectors (OPDs) have received considerable attention due to their advantages over traditional inorganic alternatives. Their attributes, including cost-effective processing, tunable bandgap capabilities, flexibility, and scalability, position them as strong candidates for the next generation of photodetection technology. In this study, we introduce photomultiplication-type organic photodetectors (PM-OPDs) utilizing non-fullerene acceptors (NFAs) with switchable functionalities. These OPDs can transition between narrowband and broadband detection modes depending on the applied bias magnitude. Additionally, the incorporation of NFAs extends the spectral response of the OPDs into the near-infrared range. In narrowband mode, the device demonstrates external quantum efficiencies exceeding 100 % at two peak wavelengths of 410 nm and 900 nm under low biases of +/- 0.3 V. When the bias is increased beyond 0.5 V, the PM-OPD transitions to broadband detection mode, encompassing a wide spectral range from 300 nm to 1000 nm. This impressive dual-mode detection capability is achieved without the need for an external optical filter or a trans-impedance amplifier, thereby simplifying the device design and reducing overall instrumentation requirements for various applications. The ability to switch between narrowband and broadband modes offers significant advantages in fields such as facial recognition, health monitoring, 3D sensing, spectroscopic applications, and optical communication. This research highlights the potential of bias-switchable PM-OPDs based on NFAs for advancing the next generation of photodetection systems.

This paper demonstrates the use of organic thin-film transistors (OTFTs) to drive active digital mini light-emitting diode (mini-LED) backlights, aiming to achieve exceptional display performance. Our findings reveal that OTFTs can effectively power mini-LED backlights, reaching brightness levels exceeding 100,000 nits. This approach not only enhances image quality but also improves energy efficiency. OTFTs offer a flexible and lightweight alternative to conventional silicon-based transistors, enabling innovative and versatile display designs. The integration of mini-LED technology with OTFTs produces displays with superior contrast ratios, enhanced color brightness, and lower power consumption. This technological advancement is poised to revolutionize high-dynamic-range (HDR) displays, including those in televisions, smartphones, and wearable devices, where the demand for high brightness and energy efficiency is paramount.

The paper investigates methods to reduce the light emission divergence angle in resonant cavity light-emitting diodes (RCLEDs) using a multilayer distributed Bragg reflector (DBR) and a microlens (ML) structure. By integrating staggered multiple quantum wells (SMQWs) and nanoporous DBRs, the study explores the effects of adjusting DBR cycles and adding microlenses. The results show that these approaches significantly reduce the emission angle, enhancing wavelength stability and device performance. This optimization is valuable for applications requiring highly directional light, such as optical communications, micro-LED displays, and augmented reality (AR).

The benzimidazole (BI)-centered acceptor IPF, featuring a perfluorophenyl (C 6 F 5 )-functionalized side chain, leverages fluorine–fluorine interactions to achieve enhanced OPV performance and stability.

In this paper, the fabrication and the corresponding performance characteristics of resonant cavity micro-light-emitting diodes (RC-μ-LEDs) are examined, with particular emphasis placed on reducing the light emission angle to enhance their application efficiency. A stepped quantum well structure and a multilayer aperture distributed Bragg reflector (DBR) are used to reduce the light emission angle, and two different approaches are investigated: one is by adding a multilayer DBR structure, and the other is by incorporating a microlens (ML) structure. The experimental results show that both adjusting the DBR cycles and adding microlenses can effectively reduce the dispersion angle of light emission, and thus improving the directionality of light, wavelength stability, and the overall device performance. Such highly directional light sources offer great solutions for optical communications, micro-LEDs, and augmented reality (AR) applications.

To address the upcoming large-scale production demands of organic photodetectors (OPDs) and image sensors, there is a growing need to develop interfacial materials that balance cost-effectiveness, performance, and stability. In this work, we systematically investigated the characteristics of a solution-processed cobalt(II) acetate (Co(OAc)2) hole transport layer (HTL) in the OPDs. The work included a detailed analysis of the suitability in both conventional and inverted device architectures, the choice of the solvent system for the precursor solution, reaction conditions, and thickness optimization. We also evaluated the performance of a Co(OAc)2 HTL in a top-illuminated device architecture to assess potential applications in image sensors. The results indicated that the device composed of a Co(OAc)2 HTL exhibited lower noise current compared to the device with vacuum-based MoO3 HTLs, and the device also demonstrated excellent stability in an unencapsulated condition. Consequently, in a top-illuminated architecture composed of a short-wave infrared (SWIR) photoactive layer, the device using Co(OAc)2 as the HTL achieved a dark current density of 1.44 x 10-5 A/cm2 and a detectivity of 1.25 x 108 Jones in the SWIR region at 1260 nm, outperforming the MoO3-based device, which exhibited a dark current density of 2.47 x 10-5 A/cm2 and a detectivity of 4.73 x 107 Jones. This solution-processed HTL meets the industrial demands for performance, stability, and cost efficiency. The Co(OAc)2 HTL has the potential to become a crucial interfacial technology in OPD development, contributing to advancements in the organic image sensor industry.

The fabrication of wide-bandgap (WBG) perovskite solar cells (PeSCs) often requires intense mixing of different halide ions, which can lead to higher defect densities in both the bulk and surfaces of the perovskite layers. In this work, efficient WBG PeSCs are developed through defect passivation using chelating materials containing phosphorus–oxygen (P = O) bonds. These chelating agents are introduced into the anti-solvents during device fabrication to effectively passivate the surface of the perovskite films. The results demonstrate that appropriate treatments with chelating agents significantly enhance both the efficiency and stability of the PeSCs. Among the tested materials, 2,8-bis(diphenyl-phosphoryl)-dibenzo[b,d]furan (PPF) shows superior performance, attributed to its effective passivation capabilities and improved charge transport properties. Notably, PeSCs treated with PPF passivation achieve a power conversion efficiency (PCE) of 12.76% under standard one-sun illumination and an impressive PCE of 38.70% under indoor light at 2000 lux. This study introduces a promising passivation strategy for the development of high-performance WBG perovskite photovoltaic devices.

This study presents a comprehensive dataset that encompasses the indoor device performance of organic photovoltaic (OPV) materials, their corresponding SMILES codes, and frontier molecular orbital (FMO) energy levels. This dataset comprises a total of 128 subsets and features 64 pairs of donors and acceptors. We demonstrate that traditional models, such as the Shockley–Queisser limit and Scharber’s model, are insufficient for accurately predicting the behavior of indoor OPVs based on the molecular orbitals of these materials. In contrast, we explore the predictive capabilities of four machine learning (ML) models for estimating the power conversion efficiencies (PCEs) of indoor OPVs, utilizing molecular structure information and FMO data from the dataset we compiled. The trained ML models exhibit strong predictive performance with high correlation coefficients (r > 0.8) for indoor PCE values; notably, the support vector regression (SVR) model achieves the highest r of 0.878. The generalization capabilities of the models are also assessed using previously unseen materials, and the results demonstrate high accuracy rates. The SVR algorithm reaches the best average accuracy of 92.1

This study introduces a novel approach for fabricating vertically stacked mini-LED arrays, integrating InGaN yellow and blue epitaxial layers with a stress buffer layer to enhance optoelectronic characteristics and structural stability. This method significantly simplifies the LED design by reducing the need for RGB configurations, thus lowering costs and system complexity. Employing vertical stacking integration technology, the design achieves high-density, efficient white light production suitable for multifunctional applications, including automotive lighting and outdoor signage. Experimental results demonstrate the exceptional performance of the stacked yellow and blue mini-LEDs in terms of luminous efficiency, wavelength precision, and thermal stability. The study also explores the performance of these LEDs under varying temperature conditions and their long-term reliability, indicating that InGaN-based yellow LEDs offer superior performance over traditional AlGaInP yellow LEDs, particularly in high-temperature environments. This technology promises significant advancements in the design and application of lighting systems, with potential implications for both automotive and general illumination markets.

Shortwave infrared (SWIR) image sensors have unique functions in many optical applications, leading to widespread attention in developing next-generation materials and photodetector technologies. Organic photodetectors (OPDs) are highly promising due to their flexibility in molecular design and processability. However, integrating OPDs with silicon readout integrated circuits (ROICs) poses numerous challenges, often resulting in underestimated device performance and limiting technological progress. To address the requirements of integrating top-illuminated OPD with ROICs and to enhance the external quantum efficiency (EQE), optical microcavities are introduced into the OPDs. The EQE in the SWIR region can be effectively enhanced by properly adjusting the thicknesses of the photoactive layer (PAL) and interlayers. Simulations of the optical field distribution further support the active functions of the microcavity structure. The spatial variation of the microcavities allows the spectral response to shift from 1000 to 1400 nm, and the optimized device achieves an EQE of 25.8% at 1260 nm. Finally, the OPDs are integrated with a silicon-based test kit, and the results reveal comparable sensing performance, demonstrating the high potential of microcavity resonance for device integration. This design effectively improves the integration of OPDs with traditional ROICs and advances SWIR-based organic image sensor technology further toward commercialization.

Narrowband organic photodetectors (OPDs) conventionally necessitate high applied biases to accommodate a sufficiently thick active layer for self-filtering functions. Herein, a concept leveraging the photomultiplication (PM) process is proposed to achieve spectral narrowing in OPDs which can operate at low external biases. This PM narrowing mechanism integrates two distinct functions through a pseudo bilayer structure comprising a photon-filtering (PF) layer and a PM layer, respectively. The initial PF layer absorbs short-wavelength photons and selectively permits light within a narrow bandwidth at the band edge of the PF material to enter the subsequent PM layer, thereby initiating the PM effect. The combined action of these two layers synergistically empowers the OPDs to exhibit a pronounced PM effect, resulting in a notably high external quantum efficiency of 5840% at a narrowband peak of 680 nm under a low bias of -5.0 V. Furthermore, the OPDs achieve a substantial -3 dB bandwidth of 5.2 kHz, alongside a maximum detectivity of 2.60 x 1013 Jones. These findings position the OPDs among the top-performing self-filtering narrowband detectors, particularly for those capable of functioning at low external biases. Narrowband organic photodetectors utilizing the photomultiplication (PM) process are implemented through a pseudo bilayer structure. The device consists of a photon-filtering (PF) layer and a PM layer. The PF layer selectively absorbs short-wavelength photons and only permits light within a narrow bandwidth to reach the PM layer. Conversely, the passing photons trigger the PM effect, resulting in remarkable self-filtering performance. image

Visible light communication (VLC), which utilizes LEDs, promises superior privacy and security and reduced impact on surrounding electronics compared to traditional Wi-Fi. This paper explores the potential of InGaN-based micro-light-emitting diodes (micro-LEDs) in high-speed VLC applications, focusing on yellow-green micro-LEDs with nanoporous distributed Bragg reflector (NP-DBR) and red InGaN micro-LEDs. Yellow-green micro-LEDs achieved a maximum external quantum efficiency (EQE) of 8.7%, bandwidth of 442 MHz, and data rate of 800 Mbit/s, while red micro-LEDs demonstrated an EQE of 5.95%, maximum bandwidth of 424 MHz, and data rate of 800 Mbit/s. The application of four core technologies, including circular devices and electrodes, reduced contact electrode area, atomic layer deposition (ALD) for passivation protection, and multi-chip parallel arrays, enhanced optoelectronic characteristics. This paper also highlights the superior performance of InGaN-based red micro-LEDs with a single quantum well (SQW) structure over double quantum wells (DQWs) for VLC applications. The SQW structure yielded higher maximum EQE, modulation bandwidth, and faster transmission rates, paving the way for the potential of full-color micro-display and high-speed VLC applications.

The technology of RGBY micro resonant cavity light emitting diodes (micro-RCLEDs) based on quantum dots (QDs) is considered one of the most promising approaches for full-color displays. In this work, we propose a novel structure combining a high color conversion efficiency (CCE) QD photoresist (QDPR) color conversion layer (CCL) with blue light micro RCLEDs, incorporating an ultra-thin yellow color filter. The additional TiO2 particles inside the QDPR CCL can scatter light and disperse QDs, thus reducing the self-aggregation phenomenon and enhancing the eventual illumination uniformity. Considering the blue light leakage, the influences of adding different color filters are investigated by illumination design software. Finally, the introduction of low-temperature atomic layer deposition (ALD) passivation protection technology at the top of the CCL can enhance the device's reliability. The introduction of RGBY four-color subpixels provides a viable path for developing low-energy consumption, high uniformity, and efficient color conversion displays.

In this research, we introduce an advanced methodology for the calculation of bulk light sources tailored for free-form surface design, focusing on the principle of energy conservation. This method is especially relevant for the evolving needs of micro-LED packaging, highlighting its potential in this burgeoning field. Our work includes the development of an algorithm for creating Freeform-Designed Chip-Scale Package (FDCSP) components. These components seamlessly integrate LEDs and lenses, underscoring our commitment to advancing free-form surface design in chip-level packaging. By adhering to the principle of energy conservation, our approach facilitates a meticulous comparison of simulation outcomes with predefined target functions. This enables the iterative correction of discrepancies, employing layering techniques to refine the design until the simulated results closely align with our goals, as demonstrated by an appropriate difference curve. The practical application of these simulations leads to the innovative design of FDCSP devices. Notably, these devices are not just suitable for traditional applications in backlight modules but are explicitly optimized for the emerging sector of micro-LED packaging. Our successful demonstration of these FDCSP devices within backlight modules represents a significant achievement. It underscores the effectiveness of our design strategy and its expansive potential to transform micro-LED packaging solutions. This research not only contributes to the theoretical understanding of energy conservation in lighting design but also paves the way for groundbreaking applications in micro-LED and backlight module technologies.

A 3628-PPI color conversion layer based on colloidal quantum dots is demonstrated with high resolution and good reliability. The sub-pixel size is 2 microns and the color conversion efficiency is as high as 22%. A properly designed mirror can enhance the peak intensity more than two times.

Herein, we proposed a unique structural design for indium gallium nitride (InGaN) based blue resonant cavity micro-light-emitting diodes (RC-μ-LEDs), focusing on the design, fabrication, and the relevant performance analyses. The proposed RC-μ-LEDs possess a three-layer staggered InGaN/GaN multiple quantum wells (MQWs) within the nanoporous Distributed Bragg Reflectors (NP-DBRs) and the conventional DBRs, introducing light confinement within such a resonant cavity. A passivation layer using atomic layer deposition (ALD) is adopted to reduce the leakage current from sidewall defects as well. Consequently, for the resulting RC-μ-LEDs, the divergence angle (DA) can be achieved down to 39.04°. While the input current increases from 1.77 A/cm² to 54 A/cm², the peak wavelength will shift from 456.16 nm to 449.18 nm, a blue shift of only 6.98 nm. Finally, we also discuss the temperature-dependent characteristics and the corresponding behaviors of our RC-μ-LEDs. Our demonstrated RC-μ-LEDs exhibit great wavelength stability with a diminished divergence angle, thus enabling full-color and low-crosstalk micro-LED displays for on-demand high-resolution applications.

The significance of shortwave infrared (SWIR) photodetectors spans across various applications. Nevertheless, the limited spectral response of silicon-based photodetectors and the high cost associated with materials like germanium (Ge) have impeded the widespread adoption of SWIR sensors, particularly in the realm of consumer electronics. This study explores the transformative impact of incorporating a cross-linkable naphthalenediimide (c-NDI) as both an electron transporting layer and a hole blocking layer in organic photodetectors (OPDs). The introduction of c-NDI as an interlayer leads to substantial enhancements in SWIR OPD performance, particularly in terms of reducing dark current and augmenting external quantum efficiency. These improvements are most notable in ultra-narrow bandgap SWIR systems, where c-NDI demonstrates superior hole-blocking capabilities. Besides, OPDs with c-NDI interlayers also exhibit exceptional stability over time when compared to OPDs based on zinc oxide interlayer, underscoring c-NDI's versatility as an interlayer. Most importantly, when compared to a commercially available Ge photodetector, c-NDI-based OPD demonstrates competitive detectivity, achieving 2.67 x 1011 Jones at a wavelength of 1300 nm. This performance even surpasses that of the Ge photodetector, highlighting the substantial potential of OPDs for SWIR imaging applications. Integrating the naphthalenediimide molecule into the organic photodetector as a hole-blocking layer can simultaneously reduce dark current and enhance quantum efficiency, resulting in outstanding detectivity of 2.67 x 1011 Jones at 1300 nm, which stands as one of the best values reported to date, and surpasses that of the germanium photodetector.image

Perovskite quantum dots (QDs) are considered as promising materials for numerous optoelectronic applications due to their narrow emission spectra, high color purity, high photoluminescence quantum yields (PLQYs), and cost-effectiveness. Herein, we synthesized various types of perovskite QDs and incorporated Au nanoparticles (NPs) to systematically investigate the impact of plasmonic effects on the photoluminescence performance of perovskite QDs. The PLQYs of the QDs are enhanced effectively upon the inclusion of Au NPs in the solutions, with an impressive PLQY approaching 99% achieved. The PL measurements reveal that the primary mechanism behind the PL improvement is the accelerated rate of radiative recombination. Furthermore, we integrate perovskite QDs and Au NPs, which function as color conversion layers, with blue light-emitting diodes (LEDs), achieving a remarkable efficiency of 140.6 lm W-1. Additionally, we prepare photopatternable thin films of perovskite QDs using photocrosslinkable polymers as the matrix. Microscale patterning of the thin films is accomplished, indicating that the addition of plasmonic NPs does not adversely affect their photopatternable properties. Overall, our research not only elucidates the underlying mechanisms of plasmonic effects on perovskite QDs but presents a practical method for enhancing their optical performance, paving the way for next-generation optoelectronic applications, including high-definition micro-LED panels.

Organic thin-film transistors (OTFTs), benefiting from a low-temperature process (≤120 °C), offer a promising approach for the monolithic integration of MicroLED structures through organic-last integration. Previous research has demonstrated that small-molecule/polymer binder-based organic semiconductor deposition, utilizing the vertical phase separation mechanism, can achieve good device uniformity while preserving high field-effect carrier mobility. However, the stability of OTFTs under light exposure at the device level remains underexplored. This study investigates the effects of various light irradiation conditions on OTFTs and delves into the underlying mechanisms of the light-trapping effect. Based on these findings, we propose an optimal OTFT design tailored for driving MicroLED displays at high operational brightness, ensuring both performance and stability.