Synthesis of TiO₂ Nanorods for Schottky‐Type UV‐Photodetectors and Third‐Generation Solar Cells

Abstract

TiO2 nanorods (NRs) are successfully synthesized on fluorine‐doped tin‐oxide pre‐coated glass substrates via hydrothermal technique. The effect of growth parameters on morphology of the synthesized NRs is investigated in detail. The results revealed that critical values for temperature, growth‐time, acidity, and precursor concentration are required for the synthesis of well‐aligned TiO2 NRs. Following the optimization of growth parameters, the well‐oriented TiO2 NRS are decorated with a thin‐sputtered layer of CdTe (CdCl2‐treated) to form a third generation inorganic‐sensitized solar cell. The power conversion efficiency associated with the constructed solar cell is found to be 0.42%, which is exactly 3.5 times larger than that obtained for the non‐CdCl2‐treated device structure. As a second part of this study, a Schottky‐type Ag/TiO2 UV‐photodetector is fabricated, which exhibited a drastic increase in photocurrent under UV‐light exposure, with a responsivity of ∼3 A W−1 for 380 nm at −1 V.

Acid-Treated PEDOT:PSS Polymer and TiO2 Nanorod Schottky Junction Ultraviolet Photodetectors with Ultrahigh External Quantum Efficiency, Detectivity, and Responsivity

“…Zou et al studied a TiO 2 /Ag-based Schottky-type photodetector and observed high responsivity (∼13 A/W) with fast response (time of 0.5 s) and recovery (time of 0.7 s). Guller et al have also studied the TiO 2 /Ag Schottky junction photodetector, and they found a high photocurrent value under UV light illumination (λ ∼ 380 nm), with responsivity of 3 A/W at an external bias of −1 V. A double-layered TiO 2 nanostructure/Au Schottky-contact-based UV photodetector was reported by Wang et al In spite of having fast response and good UV sensing properties, TiO 2 /novel metal-based Schottky junction photodetectors suffer from high fabrication cost, which arises because of the costly novel metals as well as expensive metal deposition techniques. − …”

High‐Performance Ultraviolet Photodetectors Enabled by van der Waals Schottky Junction Based on TiO2 Nanorod Arrays/Au‐Modulated Ti3C2Tx MXene

“…[6,7] Meanwhile, the construction of ultrahigh-performance photodetectors based on a 1D structure with Schottky junction has attracted much attention. [8][9][10][11] The problem of charge recombination due to the lattice mismatch between the n-layer and p-layer is overcome, however, the high state density at the TiO 2 surface will cause nonradiative charge recombination. [12] Due to the huge surface-area to volume ratios of TiO 2 NR and the dangling bonds at the surface, the holetrapping mechanism through oxygen adsorption and desorption [13,14] drastically prolongs the device response time.…”

Fast response of UV photodetector based on Ag nanoparticles embedded uniform TiO2 nanotubes array

“…These values are much higher (slower) as compared to the NTs based devices and may not be suitable for future generation faster device applications. The slow response may be due to the presence of surface defects or the slow process of oxygen adsorption or desorption in NRs [21]. These surface defects may restrict the photodetection and block the transport of photogenerated carriers, which resulted in recombination centres for them and degrade the photodetection property [17,21].…”

“…The slow response may be due to the presence of surface defects or the slow process of oxygen adsorption or desorption in NRs [21]. These surface defects may restrict the photodetection and block the transport of photogenerated carriers, which resulted in recombination centres for them and degrade the photodetection property [17,21]. It is also noteworthy to mention that the bandgap of TiO 2 NRs is 3 eV [55], which has been deviated from the UV region and gets closer to the visible region.…”

“…Apart from TiO 2 NTs, its NRs are also explored for fabricating fast and high responsive UV PDs. In this context, Xie et al and Guller et al demonstrated TiO 2 NRs based UV PD with fast photoresponse property [20,21]. However, TiO 2 nanostructures suffer from its fast recombination of excited electrons and holes, which may hinder the overall electrical performance of the devices [19].…”