Progressive Multi-Layer Drop-Casting of CdSe Nanoparticles for Photocurrent Down Shifing Monitoring

We investigated the spectroscopic photocurrent response of photovoltaic devices versus an increasing number of drop-casted CdSe nanoparticles onto planar and nanocones silicon p-i-n junctions. For all samples, a strong enhancement of the photocurrent in the UV range was detected as well as a constant increase of the photocurrent up to 20% (16%) for a planar (nanocones) junction in the range 600–800 nm. The analysis of the photocurrent versus the number of drop casted nanoparticles layers allows us to evidence a down-shifting mechanism in the U-V range and an adaptative index effect below the threshold of absorption.