ZnO thickness and ZnTe back contact effect of CdTe thin film solar cell Voc and efficiency progression

Abstract

CdTe thin film (TF) solar cells are most promising photovoltaic (PV) technology in commercial platform. Back contacts and interface defects related opto-electrical losses are still vital to limit its further technological benefit. TF PV cells shallow recombination and parasitic loss lessening purpose carrier selective back contact with band matching window layers are essential. Beside that back and front contact thickness choice is vital for field associated selective carrier collection and generous optical transmission into the active junction of the cell. It can make variation of cell efficiency. Window and front contact layers band edge variation and back contact thickness effect is analyzed by SCAPS-1D simulation software. ZnO and SnO2 front contact for CdS and CdSe window layers effect are numerically studied for 1 μm CdTe thin film PV cell. Significance of materials for front contact and its thickness effect on current density while ZnTe back surface field contact thickness effect on open circuit voltage and efficiency are demonstrated. Finally, ZnO/CdS/CdTe/ZnTe cell of 0.925 V open circuit voltage and 19.06% efficiency has been achieved for 90 nm of ZnTe with Molybdenum (Mo) back contact.

An overview on the role of ZnTe as an efficient interface in CdTe thin film solar cells: a review

“…As stated, these properties can be analyzed using different characterization tools such as X-ray diffractometer (XRD), UV-vis spectrophotometer, PL spectrometer, source meter, atomic force microscope (AFM), scanning electron microscope (SEM), and energy dispersive spectroscope (EDS). [183][184][185][186][187][188][189][190][191][192] The influence of different factors on the properties of ZnTe films is discussed in detail herein.…”

“…227 Employing the SCAPS-1D code, a ZnTe:Mo back contactcomprised CdTe device was designed based on the configuration of glass/TCO/ZnO/CdS/CdTe/ZnTe:Mo/metal contact, which predicted a V oc of 0.925 V and PCE of 19.06%. 228 Although the SCAPS 1D code has been employed, it does not consider the impact of the grain boundaries in the constituent layers, and therefore the exact mechanism is still unknown, which significantly affects the device performance. The prevalent CdCl 2 and Cu doping of the CdTe absorber were replaced by arsenic (As) to develop a Cu-free back contact, as shown in Fig.…”

“…32,42,69,70,79,80,137,199,209,211,213,218,[222][223][224][225] Review Materials Advances predicted a V oc of 0.925 V and PCE of 19.06%. 228 Although the SCAPS 1D code has been employed, it does not consider the impact of the grain boundaries in the constituent layers, and therefore the exact mechanism is still unknown, which significantly affects the device performance. The prevalent CdCl 2 treatment and Cu doping of the CdTe absorber were replaced by arsenic (As) to develop a Cu-free back contact, as shown in Fig.…”