Rational Design of Solar Cells for Efficient Solar Energy Conversion

8Highly Stable Inverted Organic Solar Cells Based on Novel Interfacial Layers

Fang Jeng Lim¹ and Ananthanarayanan Krishnamoorthy²

¹ Solar Energy Research Institute of Singapore (SERIS), National University of Singapore, Singapore

² SRM Research Institute and Department of Chemistry, SRM University, India

8.1 Introduction

Organic solar cells (OSC) based on solution‐processed semiconducting polymers have been a hot topic of research since the 1980s [1, 2]. The evolution of the OSC devices started from single organic layer [1, 3], bilayer planar heterojunction [4] to bulk heterojunction (BHJ) [5, 6] designs. BHJ structure has been widely adopted to produce more efficient devices with a record efficiency of 10.8% using thieno[3,4‐b]thiophene/benzodithiophene (PTB7), [6, 6]‐phenyl C₇₁ butyric acid methyl ester (PC₇₁BM), and an IR‐absorbing diketopyrrolopyrrole based porphyrin small molecule (DPPEZnP‐TEH) [7].

Organic solar cells present several advantages over conventional inorganic counterparts: lightweight, flexibility, semi‐transparent, easy color‐tuning, positive temperature coefficient, low energy intensive fabrication protocols, and sensitivity to low‐light condition [8]. As a result, they can be used in several niche applications where it is not possible to use conventional silicon solar cells. For instance, their flexible, lightweight, and semi‐transparent nature enables them to be integrated easily onto a variety of surfaces, such as fabrics, mobile electronics, and windows ...