Optoelectronic insights into the photovoltaic losses from photocurrent, voltage, and energy perspectives

Aixue Shang,Yidan An,Xiaofeng Li,Dong Ma

doi:10.1063/1.4990288

Abstract

Photocurrent and voltage losses are the fundamental limitations for improving the efficiency of photovoltaic devices. It is indeed that a comprehensive and quantitative differentiation of the performance degradation in solar cells will promote the understanding of photovoltaic physics as well as provide a useful guidance to design highly-efficient and cost-effective solar cells. Based on optoelectronic simulation that addresses electromagnetic and carrier-transport responses in a coupled finite-element method, we report a detailed quantitative analysis of photocurrent and voltage losses in solar cells. We not only concentrate on the wavelength-dependent photocurrent loss, but also quantify the variations of photocurrent and operating voltage under different forward electrical biases. Further, the device output power and power losses due to carrier recombination, thermalization, Joule heat, and Peltier heat are studied through the optoelectronic simulation. The deep insight into the gains and losses of the photocurrent, voltage, and energy will contribute to the accurate clarifications of the performance degradation of photovoltaic devices, enabling a better control of the photovoltaic behaviors for high performance.

Highlights

A complete analysis of solar cells (SCs), which considers the optical and electrical responses in a tightly coupled way, is very beneficial for exploring the photovoltaic science and seeking the optimal device designs for high-efficiency and low-cost.[1,2,3] To boost photovoltaic performance towards the Shockley-Queisser (SQ) limit,[4,5] effectively controlling the behaviors of photons and carriers within the SCs are critical.[6]
This paper reports an optoelectronic simulation of photovoltaic devices for quantitatively distinguishing and comparing the losses of photocurrent, operating voltage, and energy encountered in thin-film SCs
Considering that the advanced light-trapping designs for SCs have been extensively studied in these years,[26,27] we concentrate here mostly on the fundamental photovoltaic losses and the corresponding physics in terms of the optoelectronic simulation technique

Summary

INTRODUCTION

A complete analysis of solar cells (SCs), which considers the optical and electrical responses in a tightly coupled way, is very beneficial for exploring the photovoltaic science and seeking the optimal device designs for high-efficiency and low-cost.[1,2,3] To boost photovoltaic performance towards the Shockley-Queisser (SQ) limit,[4,5] effectively controlling the behaviors of photons and carriers within the SCs are critical.[6] one can hardly avoid the actual performance degradation arising from the impurity and trapping densities of semiconductor materials,[7] leading to the prominent photocurrent loss and voltage reduction. The proposed methodology is general and applicable for multi-dimensional simulation of optoelectronic devices with various semiconductor materials and device structures

MODEL AND THEORY

RESULTS AND DISCUSSIONS

CONCLUSION