Detailed study of N,N'-(diisopropylphenyl)- terrylene-3,4:11,12-bis(dicarboximide) as electron acceptor for solar cells application

TL;DR

This study investigates terrylene-3,4:11,12-bis(dicarboximide) (TDI) as an electron acceptor in P3HT-based solar cells, revealing promising charge separation but limited photocurrent due to interfacial charge extraction issues.

Contribution

It provides a detailed analysis of TDI's properties and its interaction with P3HT, highlighting its potential and challenges as an electron acceptor in solar cells.

Findings

TDI shows enhanced absorption in blends with P3HT.

Efficient exciton collection and charge separation at the donor-acceptor interface.

Formation of a TDI hole blocking layer reduces charge extraction efficiency.

Abstract

We report on terrylene-3,4:11,12-bis(dicarboximide) (TDI) as electron acceptor for bulk-heterojunction solar cells using poly(3-hexyl thiophene) (P3HT) as complementary donor component. Enhanced absorption was observed in the blend compared to pure P3HT. As shown by the very efficient photoluminescence (PL) quenching, the generated excitons are collected at the interface between the donor and acceptor, where they separate into charges which we detect by photoinduced absorption and electron-spin resonance (ESR). Time-of-flight (TOF) photoconductivity measurements reveal a good electron mobility of 10-3 cm2 V-1 s-1 in the blend. Nevertheless, the photocurrent in solar cells was found to be surprisingly low. Supported by the external quantum efficiency (EQE) spectrum as well as morphological studies by way of X-ray diffraction and atomic force microscopy, we explain our observation by the formation of a TDI hole blocking layer at the anode interface which prevents the efficiently generated charges to be extracted.