Boosting Power Conversion Efficiency of Quantum Dot-Sensitized Solar Cells by Integrating Concentrating Photovoltaic Concept with Double Photoanodes

Pei Xu,Dejun Wang,Wei Lü,Liying Wang,Xijia Yang,Xuesong Li,Xueyu Zhang,Xiaopeng Chang,Runru Liu

doi:10.1186/s11671-020-03424-8

Abstract

Despite great efforts dedicated to enhance power conversion efficiency (PCE) of quantum dot-sensitized solar cells (QDSSCs) in the past two decades, the efficiency of QDSSCs is still far behind its theoretical value. The present approaches for improving PCE are mainly focused on tailoring the bandgap of QDs to broadening light-harvesting and optimizing interfaces of component parts. Herein, a new solar cell architecture is proposed by integrating concentrating solar cell (CPV) concept into QDSSCs with double photoanode design. The Cu2S mesh is used as a counter electrode and sandwiched between two photoanodes. This designed battery structure can increase the PCE by 260% compared with a single photoanode. With the most extensively used CdS/CdSe QD sensitizers, a champion PCE of 8.28% (Voc = 0.629 V, Jsc = 32.247 mA cm−2) was achieved. This is mainly due to the increase in Jsc due to the double photoanode design and adoption of the CPV concept. In addition, another reason is that concentrated sunshine illumination induced a photothermal effect, accelerating the preceding chemical reactions associated with the conversion of polysulfide species. The cell fabrication and design reported here provides a new insight for further development of QDSSCs.

Highlights

As a kind of promising and comparably economic photoelectrical conversion device, quantum dot-sensitized solar cells (QDSSCs) have attracted great attention due to their high theoretical power conversion efficiency (PCE) [1, 2]
Zn–Cu–In–Sn alloyed Quantum dots (QDs) were used as a sensitizer, and the counter electrode (CE) is CuS doped with carbon nanotubes and graphene, which initiated a new level of the PCE of QDSSCs
The cross-sectional view in Fig. 2d indicates the existence of Cu2S film on the brass wire, the crack between them originates from cutting during the preparation of the cross-sectional sample, and the thickness is about 1.3 μ3oss-sectional samp in Fig. 2e reveals that the only elements that exist there are Cu and S, and the atom ration of Cu to S is approximately 2

Summary

Introduction

As a kind of promising and comparably economic photoelectrical conversion device, quantum dot-sensitized solar cells (QDSSCs) have attracted great attention due to their high theoretical power conversion efficiency (PCE) [1, 2]. QDSSCs inherit the structure of dye-sensitized solar cells, including photoanode Zn–Cu–In–Sn alloyed QDs were used as a sensitizer, and the counter electrode (CE) is CuS doped with carbon nanotubes and graphene, which initiated a new level of the PCE of QDSSCs. excessively decreasing the bandgap to enhance sunlight harvesting will induce the open-circuit voltage loss and decrease the device performance due to the downshift of the conduction band edge

Methods

Results

Conclusion