High-Performance Ultrabroadband Photodetector Based on Photothermoelectric Effect

Brushy C-Decorated BiTe-Based Thermoelectric Film for Efficient Photodetection and Photoimaging

Current strategies for simultaneously achieving high thermoelectric performance and high light absorption efficiency still suffer from complex steps and high costs. Herein, two kinds of amorphous thermoelectric films of n-type Bi2Te3 and p-type Bi0.5Sb1.5Te3 with high Seebeck coefficients were prepared by pulsed laser deposition (PLD) technology. In addition, C-decorated films with excellent light absorption efficiency at the junction of the thermoelectric legs were prepared by simple drop coating and reactive ion etching (RIE) method. The TE/C-RIE composite device exhibits excellent photodetection performance under the conditions of simulated natural light, monochromatic light, and high-frequency chopping. The maximum responsivity and specific detectivity of the device can reach 153.58 mV W-1 and 6.97 × 106 cm Hz1/2 W-1 (under simulated natural light), respectively. This represents an improvement rate of 85.91% compared to that of the pure TE device. Benefiting from the excellent photodetection efficiency of the device and integration advantage of PLD technology, the composite structure can be expanded into integrated photoimaging devices. The accurate identification of patterned light sources with letters (T, J, and U) and digitals (0-9) was successfully realized by associating the response electrical signals of each electrode with the position coordinates. This work provides valuable guidance for the design and fabrication of wide-spectrum photodetectors and complex optical imaging devices.

Recent Advances in Broadband Photodetectors from Infrared to Terahertz

The growing need for the multiband photodetection of a single scene has promoted the development of both multispectral coupling and broadband detection technologies. Photodetectors operating across the infrared (IR) to terahertz (THz) regions have many applications such as in optical communications, sensing imaging, material identification, and biomedical detection. In this review, we present a comprehensive overview of the latest advances in broadband photodetectors operating in the infrared to terahertz range, highlighting their classification, operating principles, and performance characteristics. We discuss the challenges faced in achieving broadband detection and summarize various strategies employed to extend the spectral response of photodetectors. Lastly, we conclude by outlining future research directions in the field of broadband photodetection, including the utilization of novel materials, artificial microstructure, and integration schemes to overcome current limitations. These innovative methodologies have the potential to achieve high-performance, ultra-broadband photodetectors.

Pulse irradiation synthesis of metal chalcogenides on flexible substrates for enhanced photothermoelectric performance

High synthesis temperatures and specific growth substrates are typically required to obtain crystalline or oriented inorganic functional thin films, posing a significant challenge for their utilization in large-scale, low-cost (opto-)electronic applications on conventional flexible substrates. Here, we explore a pulse irradiation synthesis (PIS) to prepare thermoelectric metal chalcogenide (e.g., Bi2Se3, SnSe2, and Bi2Te3) films on multiple polymeric substrates. The self-propagating combustion process enables PIS to achieve a synthesis temperature as low as 150 °C, with an ultrafast reaction completed within one second. Beyond the photothermoelectric (PTE) property, the thermal coupling between polymeric substrates and bismuth selenide films is also examined to enhance the PTE performance, resulting in a responsivity of 71.9 V/W and a response time of less than 50 ms at 1550 nm, surpassing most of its counterparts. This PIS platform offers a promising route for realizing flexible PTE or thermoelectric devices in an energy-, time-, and cost-efficient manner.