The Influence of Conduction Band Offset on CdTe Solar Cells

Chen, Yunfei; Tan, Xuehai; Shou, Peng; Cao, Xiehong; Delahoy, A. E.; Chin, Ken K.; Zhang, Chuanjun

doi:10.1007/s11664-017-5850-9

Cited by 21 publications

(8 citation statements)

References 9 publications

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“…This replacement not only avoids the current loss caused by CdS but also introduces a spike to the conduction band offset (CBO) between the buffer and CdTe absorber . Device modeling has shown that an appropriate CBO spike can reduce interface recombination and increase the open‐circuit voltages (V OC ) of CdTe solar cells . Therefore, ZMO/CdTe solar cells are expected to achieve higher efficiency due to the improvements on both short‐circuit current (J SC ) and V OC .…”

Section: Introductionmentioning

confidence: 99%

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Awni

Song

et al. 2019

Progress in Photovoltaics

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The electrical properties such as interface energy barriers, defect energy levels, and densities dictate the performance of thin film solar cells. Here, we show that these properties can be quantified in cadmium telluride (CdTe) thin‐film solar cells using admittance spectroscopy‐based techniques. Our results reveal that the electrical properties in CdTe thin‐film solar cells depend on both buffer material and the fabrication atmosphere. We find that only a negligible front contact barrier exists at the CdS/CdTe front junction regardless of the fabrication atmospheres, while an obvious front barriers are observed at the ZnMgO (ZMO)/CdTe junctions. Both CdS/CdTe and ZMO/CdTe solar cells exhibit back contact barrier. The energy level of defects is shallower in CdS/CdTe cells than in ZMO/CdTe cells. The fabrication atmosphere influences the electrical properties, i.e., an oxygen‐free atmosphere reduces the front and back barrier heights and lowers the energy level of defects. The results provide critical insights for understanding and optimizing the performance of CdTe thin‐film solar cells.

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Section: Introductionmentioning

confidence: 99%

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Awni

Song

et al. 2019

Progress in Photovoltaics

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“…Increasing the CBO of TiO 2 /N719 dye interface from 0 0.3 eV causes a decrease in PCE from 10.06 to 9.16%, respectively, due to rapid recombination of charge. On the other hand, a negative CBO (-0.1 to -0.2 eV increases the PCE from 10.06 to 10.32% ascribed to reduction of surface recombinations, 62 but suffers a degradation to 9.98% upon decreasing the CBO to -0.3 eV owing to increased surface recombination of charge carriers. 62 As ascribed in Table IV, electron affinity has a significant impact on the PV characteristics of the model cells.…”

Section: Effect Of Electron Affinity On Cell Performancementioning

confidence: 99%

Computational Simulation of a Highly Efficient Hole Transport-Free Dye-Sensitized Solar Cell Based on Titanium Oxide (TiO2) and Zinc Oxysulfide (ZnOS) Electron Transport Layers

Korir

Kibet

Ngari

2021

J. Electron. Mater.

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In order to mitigate the current global energy and environmental challenges associated with the use of fossil fuels, there is a need for better energy alternatives such as the inexhaustible solar energy. Of great interest is the design and fabrication of low-cost photovoltaic devices which are the epitome of efficient solar energy harvesting. Herein, we report inexpensive hole transport layer (HTL)-free dye-sensitized solar cell architecture with robust photovoltaic (PV) performance. In the proposed solar cell model, expensive hole transport layers, CuI, CuSCN, Spiro-OMeTAD, and PEDOT:PSS, are not required, but instead, a metallic layer is used for dye regeneration. A thorough analysis of the effect of series and shunt resistances, conduction band offset, Schottky barriers, working temperature, the metal work function of the back contact, and the electron affinities of the electron transport layers (ETLs) on the performance of the proposed solar cell is presented. The Solar Capacitance Simulator (SCAPS-1D) is used to perform the numerical simulations of the proposed solar cell design. The study focused on modeling HTL-free dye-sensitized solar cells with the configuration: FTO/ETL/N719 dye/Au. The performance of two ETLs-ZnOS and TiO 2 are critically examined. The optimized model cell performance for the FTO/ZnOS/N719 dye/Au architecture gave an optimal power conversion efficiency (PCE) of 11.54%, 62.71% as the fill factor (FF), short circuit current (Jsc) of 18.50 mAcm −2 , and an open-circuit voltage (Voc) of 0.99 V. On the other hand, the cell architecture FTO/TiO 2 / N719 dye/Au gave an optimized performance of 10.22% as the PCE, 63.58% as the FF, a Voc of 0.97 V, and 16.50 mAcm −2 as the Jsc. Based on these results, ZnOS is a suitable ETL material that has better PV performance of the solar cell device under consideration. ZnOS is earth-abundant, has a tunable band gap, is less toxic, and is, therefore, a promising candidate to replace TiO 2 ETL in future designs and manufacture of HTL-free DSSCs for commercial production.

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“…The top cell conversion efficiency is 16.9%, which is significantly below the recent record for CdTe solar cells: 22.1%. The inferior top cell performance is caused mainly by (i) the significant parasitic absorption in the CdS layer, causing a MAPC loss of around 2 mA/cm 2 , and (ii) the reduced V OC driven by increased recombination as a result of the unfavorable energy offset at the CdS/C 1−x Z x T interface [27,30]. For the record efficiency cells, more transparent ETLs, such as Mg x Zn 1−x O, and Se alloying of the CdTe absorber (to reduce the bandgap towards 1.35 eV) are utilized, which enhances the current collection at short and long wavelengths, respectively.…”

Section: Electrical Simulationsmentioning

confidence: 99%

Combined Optical-Electrical Optimization of Cd1−xZnxTe/Silicon Tandem Solar Cells

2020

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Although the fundamental limits have been established for the single junction solar cells, tandem configurations are one of the promising approaches to surpass these limits. One of the candidates for the top cell absorber is CdTe, as the CdTe photovoltaic technology has significant advantages: stability, high performance, and relatively inexpensive. In addition, it is possible to tune the CdTe bandgap by introducing, for example, Zn into the composition, forming Cd1−xZnxTe alloys, which can fulfill the Shockley–Queisser limit design criteria for tandem devices. The interdigitated back contact (IBC) silicon solar cells presented record high efficiencies recently, making them an attractive candidate for the rear cell. In this work, we present a combined optical and electrical optimization of Cd1−xZnxTe/IBC Si tandem configurations. Optical and electrical loss mechanisms are addressed, and individual layers are optimized. Alternative electron transport layers and transparent conductive electrodes are discussed for maximizing the top cell and tandem efficiency.

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The Influence of Conduction Band Offset on CdTe Solar Cells

Cited by 21 publications

References 9 publications

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Computational Simulation of a Highly Efficient Hole Transport-Free Dye-Sensitized Solar Cell Based on Titanium Oxide (TiO2) and Zinc Oxysulfide (ZnOS) Electron Transport Layers

Combined Optical-Electrical Optimization of Cd1−xZnxTe/Silicon Tandem Solar Cells

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