Achieving Record High External Quantum Efficiency >86.7% in Solar‐Blind Photoelectrochemical Photodetection

Abstract

Controlling interfacial and surface carrier dynamics associated with nanostructured semiconductors is the key to achieving outperforming electrical and optical characteristics in photoelectrochemical (PEC) devices. A strategy for surface renovation by loading a co-catalyst (functional nanoparticles or layers) can unambiguously empower the device with superior surface property. In this work, a PEC-type solar-blind photodetector based on widebandgap p-AlGaN nanowires is reported on which Rh-Cr 2 O 3 hybrid structures are rationally loaded. Impressively, the external quantum efficiency of the devices is strikingly boosted from 28.8% to 86.7%, while a record-high responsivity of 178.3 mA W −1 is achieved, exhibiting one of the highest values among PEC photodetectors. Both experimental insights and theoretical modeling reveal that the initial decoration of Rh nanoparticles facilitate the interfacial carrier transfer and separation while optimizing the hydrogen adsorption energy. After subsequent incorporation of the amorphous Cr 2 O 3 layer, which acts as a molecular sieve, not only can the side reaction over Rh be effectively suppressed, but also the interfacial carrier dynamics and surface chemical reactivity are further boosted, thus contributing to more favorable PEC processes. The work offers a unique synergetic strategy to optimize the surface property of semiconductors for boosting photoresponse performance in aqueous environments for future bio-or chemicalrelated sensing applications.

Ultrathin In2O3 Nanosheets toward High Responsivity and Rejection Ratio Visible‐Blind UV Photodetection

“…The J ph approaches saturation at a higher bias voltage of 0.6 V, as shown in Figure S5b, Supporting Information, attributing to saturation photogeneration carriers transport at higher bias voltage. Therefore, we will focus on the performance of ultrathin In reported ultrathin nanomaterial-based aqueous-type PEC UV PDs [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] and are comparable with the record-high performance of recently reported PEC UV PDs, [17] as shown in Table S9, Supporting Information. The ultrahigh UV detection capability and the operation in weak alkaline electrolyte indicate that ultrathin In 2 O 3 NSs hold great prospects for underwater UV communication [12] (more detailed comparison in Table S6, Supporting Information).…”

“…[11,12] Various wide-bandgap materials with different nanostructures have been designed for PEC VBUV PDs, [13][14][15][16] but single material-based PEC PDs usually show relatively poor photoresponse. [15,16] Some strategies have been developed for optimizing the performance of PEC VBUV PDs, such as coating heavy metal nanoparticles [17,18] and building heterojunctions, [19,20] and they inevitably increase complexity and cost. Therefore, it is important to explore more wide-bandgap semiconductors with good optical and electrical properties for building high-performance PEC VBUV PDs.…”

Self-Powered Photoelectrochemical Photodetectors Based on Electrochemically Exfoliated In2Se3 Nanosheets

“…It is worth noting that there is a transient photocurrent spike in our PEC photodetectors. This phenomenon is attributed to the surface recombination of photogenerated carriers in PEC devices . The electrolyte kind-dependent photoresponse of PEC photodetectors could be ascribed to the synergistic effect between the atomic structure of 2D In 2 Se 3 and the adsorption of anions, which will be further investigated in the following study.…”

“…This phenomenon is attributed to the surface recombination of photogenerated carriers in PEC devices. 26 The electrolyte kind-dependent photoresponse of PEC photodetectors could be ascribed to the synergistic effect between the atomic structure of 2D In 2 Se 3 and the adsorption of anions, 4 which will be further investigated in the following study. Figure 2c shows the I ph values for various concentrations and kinds of electrolytes.…”

Ordered GaN Nanorod Arrays for Self-Powered Photoelectrochemical Ultraviolet Photodetectors

“…Moreover, the response time is also an important parameter to evaluate the performance of detectors, which reflects the sensitivity of devices to UV light. In general, the rise time (τ r ) was defined as the time required from 10% to 90% of the maximum photocurrent, and the decay time (τ d ) was defined as the time to decrease from 90% to 10% of the photocurrent peak value. , As shown in Figure d, τ r and τ d of the GaN NRA2 PD are about 145 and 81 ms at 0 V bias. Interestingly, the computed response times of the NRA1 and GaN films are 85/81 and 81/82 ms, respectively, which are much smaller than that of NRA2.…”