Enhancing the Performance of Two-Terminal All-Perovskite Tandem Solar Cells by the Optical Coupling Layer Beyond the Antireflection Function

Chenbo Liu,Hang Dong,Dazheng Chen,Chunfu Zhang,Zeyang Zhang,Shangzheng Pang,Weidong Zhu,Jincheng Zhang,Yue Hao

doi:10.1109/jphot.2020.3021529

Abstract

All-perovskite tandem solar cells have great potential to realize the efficiency beyond the Shockley-Queisser efficiency limitation of single junction solar cells. Here we investigate the photon redistribution effect induced by introduction of the optical coupling layer in two terminal (2 T) tandem solar cells. In this work, it is shown that the introduction of the optical coupling layer could not only reduce the reflection loss, but also would affect the redistribution of the absorbed photons in the tandem device due to the optical interference effect, which will disturb the previous balance and complicate the optical modulation. This photon redistribution phenomenon is systemically investigated by combining the optical and electrical aspects. By considering the coupling effect beyond the antireflection function after introducing the optical coupling layer, the new current match could be achieved, which would obviously improve the device performance further. Various materials such as LiF, MgF 2 , Al 2 O 3 , ZnO have been adopted as the optical coupling layer and it is demonstrated that this phenomenon is universal for all the cases. The improvement brought by photon redistribution effect may be even more obvious than antireflection function. Through analyzing the inner optical mechanism and modulating the structure, a higher performance can be achieved by carefully considering the optical coupling effect.

Highlights

Metal halide perovskites have attracted immense interest due to their low-cost, adjustable bandgap and high absorption coefficient [1]–[3]
Synergetic adjustment of the optical coupling layer and the perovskite absorption layers is investigated for the device performance improvement [19]–[20]. Optical materials such as LiF, MgF2, ZnO, and Al2O3, which are widely employed in perovskite tandem solar cells [21]–[23], are employed as optical coupling layers to demonstrate the common influence of optical coupling effect on device
The photon redistribution phenomenon induced by the optical coupling layer and its influence on the performance of the 2 T all-perovskite tandem cell is systemically explored through optical and electrical analysis at the same time

Summary

Introduction

Metal halide perovskites have attracted immense interest due to their low-cost, adjustable bandgap and high absorption coefficient [1]–[3]. Much progress has been made in the research about narrow bandgap PSCs and the PCE of 18.4% has been obtained for 1.25 eV (FASnI3)0.6(MAPbI3)0.4 in 2018 [13] These developments about narrow bandgap PSCs have paved the way toward the all-perovskite tandem cells, which are considered to have massive potential for commercial applications. Synergetic adjustment of the optical coupling layer and the perovskite absorption layers is investigated for the device performance improvement [19]–[20]. Optical materials such as LiF, MgF2, ZnO, and Al2O3, which are widely employed in perovskite tandem solar cells [21]–[23], are employed as optical coupling layers to demonstrate the common influence of optical coupling effect on device. Through analyzing the inner optical mechanism and optimizing the optical modulation, it is demonstrated that an obviously improved performance can be obtained by considering the synergetic modulation of the optical coupling layers and the perovskite absorption layers

Optical and Electrical Calculation Methods

Results and Discussion

Conclusions