Efficient Environmentally Friendly Flexible CZTSSe/ZnO Solar Cells by Optimizing ZnO Buffer Layers

Abstract

Flexible CZTSSe solar cells have attracted much attention due to their earth-abundant elements, high stability, and wide application prospects. However, the environmental problems caused by the high toxicity of the Cd in the buffer layers restrict the development of flexible CZTSSe solar cells. Herein, we develop a Cd-free flexible CZTSSe/ZnO solar cell. The influences of the ZnO films on device performances are investigated. The light absorption capacity of flexible CZTSSe solar cells is enhanced due to the removal of the CdS layer. The optimal thickness of the ZnO buffer layers and the appropriate annealing temperature of the CZTSSe/ZnO are 100 nm and 200 °C. Ultimately, the optimum flexible CZTSSe/ZnO device achieves an efficiency of 5.0%, which is the highest efficiency for flexible CZTSSe/ZnO solar cells. The systematic characterizations indicate that the flexible CZTSSe/ZnO solar cells based on the optimal conditions achieved quality heterojunction, low defect density and better charge transfer capability. This work provides a new strategy for the development of the environmentally friendly and low-cost flexible CZTSSe solar cells.

Highly efficient emerging Ag2BaTiSe4 solar cells using a new class of alkaline earth metal-based chalcogenide buffers alternative to CdS

“…This, in turn, negatively impacts the spectral response of the solar cell 53 , 62 , 69 , 70 . On the other hand, if the buffer is too thick (over 0.1 µm), it leads to parasitic absorption, reducing the amount of charge carriers that reach the absorber, and reducing the built-in potential at the interface, which makes it harder to generate and collect charge carriers 62 , 70 , 71 . To achieve high PCE, it’s recommended to use a buffer thickness in the range of 0.05 to 0.1 µm for I 2 -II-IV-VI 4 solar cells as found in the literature 16 , 51 , 55 , 58 , 71 .…”

“…On the other hand, if the buffer is too thick (over 0.1 µm), it leads to parasitic absorption, reducing the amount of charge carriers that reach the absorber, and reducing the built-in potential at the interface, which makes it harder to generate and collect charge carriers 62 , 70 , 71 . To achieve high PCE, it’s recommended to use a buffer thickness in the range of 0.05 to 0.1 µm for I 2 -II-IV-VI 4 solar cells as found in the literature 16 , 51 , 55 , 58 , 71 . After considering all these factors, an optimal thickness of 0.080 µm is selected for the alkaline earth metal-based chalcogenide buffers, which falls within the suggested range.…”

Preparation of ZnO Nanosheet Array and Research on ZnO/PANI/ZnO Ultraviolet Photodetector

“…It has good thermal and chemical stability, and is low-cost and easy to obtain. It has been identified as one of the most effective antireflective semiconductor materials for optical detecting applications [22,23] and is widely used in various fields, including UV ultraviolet optoelectronic devices [24], solar cells [25] and light-emitting diodes [26]. However, ZnO is susceptible to corrosion by light, resulting in low visible light utilization efficiency, high recombination rate of photogenerated electron hole pairs and low quantum efficiency, and it is challenging to obtain stable performance due to the inherent self-compensation effect of its donor.…”

Spin-Coated CZTS Film with a Gradient Cu-Deficient Interfacial Layer for Solar Hydrogen Evolution

“…Photoelectric properties of the CZTS-based photocathode . To elucidate the electrochemical charge-transfer kinetics and interface carrier transport mechanism of CZTS-based photocathodes with the introduction of the GCD-layer, we conducted electrochemical impedance spectroscopy (EIS), which is an effective technique to study the polarization resistance ( R P ) of photocathodes by applying sinusoidal AC signals. ,, Figure a shows the Nyquist plots of CZTS, CZTS-8-8-8, CZTS-8-6-6, and CZTS-8-6-4 photocathodes measured under AM 1.5 G simulated solar radiation at 0.2 V RHE . As illustrated, a widely used equivalent circuit model was employed for curve fitting, − consisting of a series resistance ( R S ) and parallel combination of polarization resistance ( R P ) and constant phase element (CPE), which represent the high-frequency capture and semicircle in the Nyquist plots of CZTS photocathodes, respectively.…”