A Flexible Self‐Powered UV Photodetector and Optical UV Filter Based on β‐Bi₂O₃/SnO₂ Quantum Dots Schottky Heterojunction

Abstract

Recently reported ultraviolet (UV) detectors majorly focus on exploration of photodetection properties like photon absorption and electron‐hole pair generation to improve the photoresponsivity. However, UV sensors also have a potential advantage of monitoring the excessive UV exposure on skin. In this work, bismuth oxide/SnO2 quantum dots (QDs) vertical‐junction‐based self‐powered UV photodetector and optical UV filter are demonstrated. β‐Bi2O3 nanofibers are synthesized via electrospinning technique and SnO2 QDs are synthesized using a facile, single step hydrothermal process. Detailed morphological studies reveal the formation of 1D‐Bi2O3 and 0D‐SnO2. The fabricated self‐powered Bi2O2/SnO2‐based p–n heterojunction device exhibits a maximum responsivity of 62.5 µA W−1 and specific detectivity (D*) of 4.5 × 109 Jones attributing to the high absorption coefficient of β‐Bi2O2 nanofibers and SnO2 QDs in the UV region. Further, the 1D β‐Bi2O3 nanofibers and 0D SnO2 QDs are coated onto disposable cloth substrate to fabricate the UV optical filter which exhibits an exceptional ultraviolet protection factor of 159 and the photodetector device demonstrates high stability and reproducibility even after 1000 bending cycles. The strategy outlined here paves the way for development of bifunctional, cost‐effective design and construction of wearable UV sensors and protective devices for advanced nano‐electronic applications.

A self-powered high performance UV-Vis-NIR broadband photodetector based on β-Bi2O3 nanoparticles through defect engineering

“…As shown in Table 1, the parameters of the Bi 2 O 3 photodetector in this work are compared with some other related metal oxides photodetectors. 43,[50][51][52][53][54] It is noteworthy that the Bi 2 O 3 photodetector in this work exhibits a wide detection range in the UV-Vis-NIR region, while the previous Bi 2 O 3 photodetectors based on metal-semiconductor-metal-type 55 On the other hand, the holes flow to the polysulfide electrolyte and undergo oxidation reaction with S 2À Ox:…”

“…As shown in Table 1, the parameters of the Bi 2 O 3 photodetector in this work are compared with some other related metal oxides photodetectors. 43,50–54 It is noteworthy that the Bi 2 O 3 photodetector in this work exhibits a wide detection range in the UV-Vis-NIR region, while the previous Bi 2 O 3 photodetectors based on metal–semiconductor–metal-type (MSM-type) and PEC-type structures can only detect light in the UV region. 43,50 Moreover, the Bi 2 O 3 photodetector in this work has a high responsivity of 29.92 mA W −1 (second only to that of the Se/TiO 2 heterojunction), accompanied by a high specific detectivity of 7.46 × 10 10 Jones and a fast rise time of 20 ms.…”

“…6(e), a maximum specific detectivity of 7.46 × 10 10 Jones is obtained under a relatively weak light power of 5 mW cm −2 , which is higher than the previously reported β-Bi 2 O 3 /SnO 2 specific detectivity of 4.5 × 10 9 Jones. 43 Moreover, the specific detectivity increases with the decrease of the light power, owing to the logarithmic change of the photovoltage with the increase of the light power. 44 Furthermore, the correlation between the net photocurrent and the light power conforms to the following power law relationship: 45,46 I ph ∼ P θ Here, I ph ( I ph = I light − I dark ) is the net photocurrent, and the fitting parameter θ in Fig.…”

“…MSM-type) and PEC-type structures can only detect light in the UV region 43,50. Moreover, the Bi2 O 3 photodetector in this work has a high responsivity of 29.92 mA W À1 (second only to that of the Se/TiO 2 heterojunction), accompanied by a high specific detectivity of 7.46 Â 10 10 Jones and a fast rise time of 20 ms.…”

Self-Powered Photodetector Based on FTO/n-TiO2/p-CuMnO2 Transparent Thin Films

“…Over time, it was shown that metal oxide heterojunctions can facilitate photovoltaics for self-powered operation due to their built-in potential, low cost, non-toxicity and easy synthesis methods [ 6 ]. Thus, a self-powered UV photodetector based on a p - n heterojunction has a main advantage due to its built-in potential that automatically separates generated electron-hole pairs [ 7 ]. Therefore, various metal oxide semiconductor materials (i.e., TiO 2 , ZnO, CuO and NiO) have been applied for different types of photovoltaic cells [ 8 , 9 ], but from them, TiO 2 was selected as the most desirable material for photovoltaic devices [ 10 ].…”