Effect of pulse bias voltages on performance of CdTe thin film solar cells prepared by pulsed laser deposition

摘要

A new method of efficiency of CdTe thin film solar cells has been proposed. In view of the characteristics of pulsed laser deposition (PLD) and combined with high power pulse bias power supply, CdTe thin films under 0, 500, 750, and 1000 V pulse bias were prepared on FTO substrates, and solar cells with FTO/CdS/CdTe/Au structure were formed. The crystal structure, vibration mode, morphology, and optical properties of the CdTe thin films deposited at different pulse bias were studied by XRD, Raman, SEM, UV-Vis spectrophotometer measurement. X-ray diffraction analysis indicated the prepared CdTe thin films had a strong (111) preferentially oriented cubic sphalerite structure. The transmission spectrum showed that with the increase of pulse bias, the absorption of CdTe films gradually moved towards the long-wave direction, and the optical bandgap decreased from 1.516 to 1.485 eV. We further fabricated FTO/CdS /CdTe/Au solar cells, with improved efficiency from 2.29% to 6.07% and excellent response performance over a long-wavelength range of over 900 nm, and the pulse bias voltage effect was significant.