Numerical study on the angular light trapping of the energy yield of organic solar cells with an optical cavity

Jonathan Lehr,Jordi Martorell,Ulrich W Paetzold,Uli Lemmer,Adrian Mertens,Quan Liu

doi:10.1364/oe.404969

Abstract

A limiting factor in organic solar cells (OSCs) is the incomplete absorption in the thin absorber layer. One concept to enhance absorption is to apply an optical cavity design. In this study, the performance of an OSC with cavity is evaluated. By means of a comprehensive energy yield (EY) model, the improvement is demonstrated by applying realistic sky irradiance, covering a wide range of incidence angles. The relative enhancement in EY for different locations is found to be 11-14% compared to the reference device with an indium tin oxide front electrode. The study highlights the improved angular light absorption as well as the angular robustness of an OSC with cavity.

Highlights

Organic photovoltaics (OPV) offers a low-cost alternative to silicon (Si) photovoltaics (PV) by utilizing abundant materials and featuring mechanical flexibility and simple fabrication techniques [1,2,3]
We have studied the suitability of an optical resonator architecture for enhancing the power output of an organic solar cells (OSCs) under realistic outdoor conditions
The resulting gain is attributed to the enhanced light trapping and further to a reduced RS due to the thin metallic front electrode

Summary

Introduction

Organic photovoltaics (OPV) offers a low-cost alternative to silicon (Si) photovoltaics (PV) by utilizing abundant materials and featuring mechanical flexibility and simple fabrication techniques [1,2,3]. The maximal efficiency gain of a solar cell with cavity configuration was investigated by optimizing the layer stack and comparing it to a conventional OSC containing an ITO front electrode [13,18]. In order to demonstrate the mechanism of light absorption by utilizing resonant modes, the number of absorbed photons under AM1.5 g irradiation is shown in Fig. 3 as a function of the PTB7-Th:PC71BM ab1s0orber layer thickness.

Results

Conclusion