Uncooled Short-Wave Infrared Sensor Based on PbS Quantum Dots Using ZnO NPs

Abstract

Shortwave infrared (SWIR) sensors have attracted interest due to their usefulness in applications like military and medical equipment. SWIR sensors based on various materials are currently being studied. However, most SWIR detectors need additional optical filters and cooling systems to detect specific wavelengths. In order to overcome these limitations, we proposed a solution processed SWIR sensor that can operate at room temperature using lead chloride (PbS) QDs as a photoactive layer. Additionally, we adapted zinc oxide (ZnO) nanoparticles (NPs) as an electron transport layer (ETL) to improve the sensitivity of a PbS SWIR sensor. In this study, PbS SWIR sensors with and without a ZnO NPs layer were fabricated and their current–voltage (I–V) characteristics were measured. The on/off ratio of the PbS SWIR sensor with ZnO NPs was 2.87 times higher than that of the PbS SWIR sensor without ZnO NPs at the maximum current difference. The PbS SWIR sensor with ZnO NPs showed more stable current characteristics than that without ZnO NPs because of the ZnO NPs’ high electron mobility and proper lowest unoccupied molecular orbital (LUMO) level.

Air-stable and ultrasensitive solution-cast SWIR photodetectors utilizing modified core/shell colloidal quantum dots

“…PbS QDs were synthesized according to the previously reported literature [33,38,39], and then used to produce PbS/CdS core/shell QDs. The CdS shell was grown by the exchange of Pb 2+ ions with Cd 2+ ions at the surface of PbS QDs.…”

“…PbS QDs were prepared using similar previously reported methods with modifications [33,38,39]. In a typical synthesis, two separate solutions containing 1 mmol of PbCl 2 and 0.36 mmol of sulfur in 2.4 mL and 0.24 mL of OLA, respectively, were stirred for 30 min at room temperature under Ar gas flow.…”

“…By analyzing passivated QDs, we confirmed not only the photostability but also the efficient carrier dynamics and improved lifetime of SWIR photodetectors. To evaluate their performance, we fabricated solution-processable SWIR photodetectors by employing a modification of previously reported methods [38].…”

Nanostructured Lead Sulphide Depositions by AACVD Technique Using Bis(Isobutyldithiophosphinato)Lead(II) Complex as Single Source Precursor and Its Impedance Study

“…For example, over a wide range of nonstoichiometry, their lattice structure remains stable, and they also exhibit positive temperature coefficients (dEg/d T ) as compared to all other semiconductors, which have negative temperature coefficients. Lead sulfide belongs to the chalcogenides semiconductors family, having a direct bulk band gap of 0.41 eV at room temperature [ 1 ]. This narrow band gap widens its application in photovoltaic cells [ 2 ], infrared detectors [ 3 ], thermoelectrics [ 4 ], dielectrics [ 5 ], gas sensing [ 6 ], biosensing [ 7 ] and photocatalytic applications [ 8 ].…”

Current-Mode Self-Amplified CMOS Sensor Intended for 2D Temperature Microgradients Measurement and Imaging

“…Many contributions to temperature sensors and temperature imagers are available in the corresponding technical literature. Regarding the uncooled thermal image sensors, some papers present contributions considering area reduction, enhancement of responsivity and sensitivity, signal readout process, image processing, power consumption and noise equivalent temperature difference (NETD) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. It is desirable to have these sensors integrated into standard CMOS technology to reduce the costs and to facilitate embedding the interface and the readout electronic circuitry [ 1 , 2 , 4 , 5 , 7 , 10 , 11 , 12 , 17 , 18 ].…”