Numerical approach to optimizing the doping concentration of the absorber layer to enhance the performance of a CdTe solar cell

Abstract

Cadmium telluride (CdTe)-based solar cells have been proving their potential for high efficiency performance for several decades. However, efficient p-type doping of CdTe has remained a critical challenge for decades thus limiting the performance of this type of solar cell. Thus, this work intends to assess the effects of various dopants and their optimization in order to obtain efficient photovoltaic (PV) performances. In the process we used numerical simulation software SCAPS-1D as it expedites and facilitates the modeling of a solar cell through optimizations and variations. The studied CdTe solar cell structure comprises multi-junction semiconductor layers such as n-ITO/n-ZnO/n-CdS/p-CdTe in a superstrate structure. Three different types of absorber layer dopants such as copper (Cu), silver (Ag) and arsenic (As) are used, respectively. The work started with the optimization of carrier concentration followed by the variation of the thickness of the absorber layer. The PV performances in terms of open-circuit voltage, short-circuit current density, fill factor and efficiency are presented and, after comparison, the As dopant is shown to be a promising candidate. Also, the working temperature is varied to obtain a suitable environment under which the solar cell can work efficiently.

Maximizing the solar output power using hybrid (CdS/ZnSe) buffer for CIGS thin film solar cell

“…As a result, augmented values of solar cell performance parameters are found [31] However, the performance parameters have a considerably slower acceleration when the layer thickness is over 2.5 μm because that enhances the recombination rate as well [32]. Though performance parameters have not increased at a very commendable rate beyond 1.5 μm, the optimization of absorber thickness is done at 2.5 μm as at lower thickness recombination dominates over the generation of electron-hole pair which can be a negative aspect in terms of device performance experimentally [33].…”

“…Again, the diffusion length of the minority carrier along with space charge region (SCR) width is curtailed at a large carrier concentration that stimulates the carrier collection probability within it. As a result, the performance of the device improves [33]. However, the carrier recombination in the bulk increases on account of the high electric field which leads to a drop in short circuit current [31].…”

Effect of Cu2Te Back Surface Interfacial Layer on Cadmium Telluride Thin Film Solar Cell Performance from Numerical Analysis

“…Since CdTe solar cell is a heterojunction, absorption from other layers within the visible-light range with defect parameters significantly tends to affect the spectral response analysis in the simulation [62]. Moreover, a higher acceptor concentration in the order of 10 16 cm −3 to 10 18 cm −3 tends to limit the space charge region's width, leading to the decrease of photon collection, as well as defects acting as recombination centers [63]. From the simulated EQE, it is also observed that higher acceptor concentration leads to Jsc-JV loss, primarily due to loss of long-wavelength photo-generated carriers.…”