Jonathan Austin¹,Nathan Cotttam¹,Jonathan Gosling¹,Chengxi Zhang²,Feiran Wang¹,Tyler James¹,Peter Beton¹,Yundong Zhou³,Gustavo Trindade³,Christopher Tuck¹,Richard Hague¹,Oleg Makarovsky¹,Lyudmila Turyanska¹

The University of Nottingham¹,Shanghai University²,National Physical Laboratory³

Abstract

The University of Nottingham¹,Shanghai University²,National Physical Laboratory³

Photodetectors based on low-dimensional materials are promising candidates for next generation optoelectronic devices and over the past decade the photoresponsivity of these devices has improved drastically due to material innovations [1]. All-inorganic perovskite nanocrystals (NCs) have been of particular interest owing to their high absorption cross-sections, long carrier diffusion lengths, tunable optical properties, and improved stability compared to other perovskite materials [2,3]. This stability enables the use of new manufacturing methods, specifically inkjet printing, which offers a promising route for scalable fabrication of devices with a high degree of design freedom and opportunities for device fabrication on flexible substrates [3-5]. Here we report a novel formulation of all-inorganic CsPbBr3 and CsPb(Br/I)3 NC inks for inkjet printing thin films over large areas and demonstrate high precision fabrication of complex photoluminescent patterns on rigid and flexible substrates. These films are used to photosensitise chemical vapour deposition (CVD) grown graphene transistors increasing their photoresponsivity to 107 A/W in the VIS-UV range [6], which is greater than that of any other inkjet-printed device recorded in the literature (R = 104 A/W [7]). We also fabricated fully printed photodetectors by incorporating inkjet-printed graphene (iGr) and printed Au electrodes. The fully printed CsPb(Br/I)3/iGr photodetector displayed a maximum responsivity of 10 A/W [6], which to our knowledge is the largest responsivity reported for this type of device (R = 10-1 A/W [8]). The performance of these devices is analysed and explained using modelling of charge transport through functionalised graphene and graphene networks [5] and explained by slow carrier dynamics governed by complex charging processes [9]. For reduced manufacturing complexity, we formulated and printed a hybrid ink containing both iGr and CsPbX3 NCs (iGr-CsPbX3) to produce photodetectors in a single deposition step on rigid and flexible substrates. In these detectors a single hybrid iGr-CsPbX3 film acts as both photosensitive and conductive layer and achieved a maximum responsivity of 10-2 A/W, with negligible change in conductivity up to 200 bending cycles [6]. This work demonstrates successful integration of low-dimensional materials with additive manufacturing technologies and highlights its potential for scalable and customisable production of optoelectronic devices on rigid and flexible substrates. References: [1] A. Chetia et al. Mater. Today Commun., 2022, 30, 103224 [2] N D. Cottam, et al. ACS Appl. Electron. Mater., 2020, 2, 147. [3] F. Mathies, et al. Energy Technol., 2020, 8, 1900991. [4] J. Liu, et al. Adv. Mater, 2019, 31, 1901644. [5] F. Wang, J.H. Gosling, et al. Adv. Funct. Mater., 2021, 31, 200478 [6] J S. Austin, et al. Manuscript in preparation, 2022 [7] M. J. Grotevent, et al. Adv. Sci., 2021, 8, 2003360. [8] A M. Alamri, et al. IEEE Trans. Electron Devices., 2019, 66, 2657 [9] N. D. Cottam, et al. under review, Adv. Electron. Mater., 2022