Concepedia

Polymer—perylene diimide heterojunction solar cells

Alison J. Breeze, Ashley Salomon, David S. Ginley, Brian A. Gregg, H. Tillmann, H.‐H. Hörhold

Applied Physics Letters · 2002 · 143 citations · 29 references

TL;DR

The study investigates how reversing the order of the photoactive layers, while keeping the electrode configuration unchanged, affects the photovoltage of polymer–perylene diimide heterojunction solar cells. The authors reverse the layer sequence and compare the resulting hybrid bilayer devices to analogous pure small‑molecule bilayers to evaluate factors that influence device efficiency. Hybrid bilayer cells reach a 0.71% power‑conversion efficiency, and the results demonstrate that the properties of the organic layers and the ordering of their band offsets determine the direction and polarity of photocurrent and photovoltage, with comparisons to pure small‑molecule bilayers revealing key efficiency‑influencing factors.

Abstract

Thin-film small molecule/polymer hybrid bilayer photovoltaic cells have been constructed, exhibiting power conversion efficiencies of 0.71% under 80 mW/cm2 white light illumination. The parameters influencing the photovoltage of these devices are explored by reversing the order of the photoactive layers while maintaining the same electrode configuration. It has been found that the properties of the organic photoactive layers play an important role in determining the direction of current flow and the photovoltage of the device. Comparison is made to analogous pure small molecule bilayer devices, and conclusions about some of the factors influencing device efficiency are drawn. It has been shown that ordering of the band offsets of the two organic materials plays an important role in determining the polarity of the photocurrent and the photovoltage of the device.