Hybrid ZnO-organic semiconductor interfaces in photodetectors: A comparison of two near-infrared donor-acceptor copolymers

Pickett, Alec and Mohapatra, Abhisek and Laudari, Amrit and Khanra, Soma and Ram, Thulasi and Patil, Satish and Guha, Suchismita (2017) Hybrid ZnO-organic semiconductor interfaces in photodetectors: A comparison of two near-infrared donor-acceptor copolymers. In: ORGANIC ELECTRONICS, 45 . pp. 115-123.

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Abstract

Hybrid organic-inorganic photodiode interfaces have gained significant interest due to their unique physical properties such as mechanical flexibility and high photosensitivity. Two diketopyrrolopyrrole (DPP)-based donor-acceptor copolymers with different backbone conformations are characterized in an inverted non-fullerene photodiode architecture using ZnO nano-patterned films as the electron transport layer. The DPP copolymer with a thienothiophene unit (PBDT-TIDPP) is more planar and rigid compared to the DPP system with a thiophene unit connecting the donor and acceptor moieties within the monomer (PBDT-TDPP). The hybrid interfaces were optimized by using poly(3-hexylthiophene) (P3HT) as the p-type layer for monitoring the critical thickness and morphology of the ZnO layer. The maximum photoresponsivity from a P3HT:ZnO photodiode was found to be 56 mA/W. The photoresponsivity of PBDT-TTDPP:ZnO photodiodes were found to be more than two orders of magnitude higher than PBDT-TDPP:ZnO photodiodes, which is attributed to an enhanced transport of carriers due to the planar backbone conformation of the PBDT-TTDPP copolymer. Capacitance-voltage measurements from hybrid Schottky barrier interfaces further shed light into the nature of photocarriers and device parameters. First-principles time-dependent density-functional theoretical calculations yield a higher absorptivity for the PBDT-TTDPP dimer compared to PBDT-TDPP. (C) 2017 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	ORGANIC ELECTRONICS
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	10 Jun 2017 04:38
Last Modified:	10 Jun 2017 04:38
URI:	http://eprints.iisc.ac.in/id/eprint/57150

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