Evaluation of Polymer Solar Cell Efficiency To Understand the Burn-in Loss

Kesavan, Arul Varman and Khanum, Khadija Kanwal and Subbiahraj, Saravanan and Ramamurthy, Praveen C (2019) Evaluation of Polymer Solar Cell Efficiency To Understand the Burn-in Loss. In: JOURNAL OF PHYSICAL CHEMISTRY C, 123 (37). pp. 22699-22705.

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Abstract

In this study, the degradation process of a conventional P3HT:PC61BM bulk heterojunction solar cell device due to light-induced aging is evaluated. This structure is chosen so as to reduce the number of interface layers. Continuous light aging is done under AM1.5G light, and devices are analyzed in short periods. The measured electrical properties, such as current-voltage, capacitance-voltage, and capacitance-frequency characteristics, and optical and structural properties suggested the process of device degradation progression. In order to investigate the photodegradation of the device and the trap state formation, various device parameters are determined, such as the density of trap states, trap distribution width, peak trap state position, carrier concentration, and built-in potential. The dual peak nature is observed in the capacitance-voltage spectra of the light-aged device. Formation of defect peaks should be attributed to trap states as well as morphological changes: modification at the donor/acceptor and semiconductor/electrode interface. Additionally, the defect peak intensity increases as the light aging period increases. The calculated carrier concentration and density of trap states are observed to be correlated with the device performance. The detailed analysis of the device properties indicates that interface-induced changes are the initial points of device degradation. The initial point of degradation primarily affects short-circuit current and fill factor (FF). Observed changes in the current density, J(SC), and FF are mainly associated with an increase in the series resistance, R-s. Structural and optical properties of as-prepared and aged devices revealed that there is not much change in the absorbance and crystallinity. These results corroborate that the initial device degradation is mainly due to the electrical part (various resistance) associated with the device. Further, the doublet in the capacitance spectrum under the illuminated condition is discussed. The burn-in loss of the solar cell is connected with an increase in the density of trap states. This work provides direct evidence of the formation of defect states in the device, which is portrayed in the capacitance-voltage spectra of aged samples under the illuminated condition.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY C
Publisher:	AMER CHEMICAL SOC
Additional Information:	copyright for this article belongs to AMER CHEMICAL SOC
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	22 Oct 2019 09:44
Last Modified:	22 Oct 2019 09:44
URI:	http://eprints.iisc.ac.in/id/eprint/63778

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