Enhanced Charge Transport and Photovoltaic Performance of PBDTTT-C-T/PC70BM Solar Cells via UV-ozone Treatment

Prajwal Adhikary, Swaminathan Venkatesan, Nirmal Adhikari, Purna P Maharjan, Olusegun Adebanjo, Jihua Chen, Qiquan Qiao

Nanoscale. 2013 Oct 21;5(20):10007-13.

PMID: 23994892

Abstract:

In this work, the electron transport layer of PBDTTT-C-T/PC70BM polymer solar cells were subjected to UV-ozone treatment, leading to improved cell performances from 6.46% to 8.34%. The solar cell efficiency reached a maximum of 8.34% after an optimal 5 minute UV-ozone treatment, and then decreased if treated for a longer time. To the best of our knowledge, the mechanism behind the effects of UV-ozone treatment on the improvement of charge transport and cell performance is not fully understood. We have developed a fundamental understanding of the UV-ozone treatment mechanism, which explains both the enhancements in charge transport and photovoltaic performance at an optimal treatment time, and also the phenomenon whereby further treatment time leads to a drop in cell efficiency. Transient photocurrent measurements indicated that the cell charge transport times were 1370 ns, 770 ns, 832 ns, 867 ns, and 1150 ns for the 0 min, 5 min, 10 min, 15 min, and 20 min UV-ozone treatment times, respectively. Therefore the 5 min UV-ozone treatment time led to the shortest transport time and the most efficient charge transport in the cells. The 5 min UV-ozone treated sample exhibited the highest peak intensity (E2) in the Raman spectra of the treated films, at about 437 cm(-1), indicating that it possessed the best wurtzite phase crystallinity of the ZnO films. Further increasing the UV-ozone treatment time from 5 to 20 min induced the formation of p-type defects (e.g. interstitial oxygen atoms), pushing the ZnO Fermi-level further away from the vacuum level, and decreasing the wurtzite crystallinity.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP1393932530	PBDTTT-C-T		1393932-53-0	Price

Catalog Number

Product Name

Structure

CAS Number

Price

AP1393932530

PBDTTT-C-T

1393932-53-0

Price

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