Metal halide-based perovskites,with their exceptional photoelectric conversion efficiency,are promising materials for photodetectors and image sensors.Achieving high-definition optical imaging requires not only high-q...Metal halide-based perovskites,with their exceptional photoelectric conversion efficiency,are promising materials for photodetectors and image sensors.Achieving high-definition optical imaging requires not only high-quality perovskite materials but also effective patterning methods.Here,we show the fabrication of pixelated photodetector arrays through a two-step process:(1)direct optical patterning of CsPbBr_(3) perovskite nanocrystal films using ligand cross-linkers,and(2)post-patterning ligand-exchange process.The direct optical patterning achieves high-resolution(≈2μm in pixel sizes),uniform CsPbBr_(3)nanocrystal film patterns over 2-inch wafers.The ligand-exchange process replaces the long hydrocarbon ligands and cross-linkers with compact ionic ligands,which enhance the charge transport efficacy without compromising the quality of the patterned films.Consequently,the patterned photodetectors,in the photoconductor configuration,show responsivity(0.11 A·W^(-1))and specific detectivity(1.81×10^(11)Jones)on par with their non-patterned counterparts.These features permit the creation of pixelated photodetector arrays that minimize the charge-sharing crosstalk effect and enable improved imaging capabilities.This work shows a promising approach in building high-performance perovskite image sensors.展开更多
Direct photopatterning is a powerful strategy for patterning colloidal quantum dots(QDs)for their integration in various electronic and optoelectronic devices.However,ultraviolet(UV)exposure required for QD patterning...Direct photopatterning is a powerful strategy for patterning colloidal quantum dots(QDs)for their integration in various electronic and optoelectronic devices.However,ultraviolet(UV)exposure required for QD patterning,especially those with short wavelength(e.g.,deep UV light),can degrade the photo-,and electroluminescence,and other properties of patterned QDs.Here we develop a photosensitizer-assisted approach for direct photopatterning of QDs with h-line(centered at 405 nm)UV light and better preservation of their luminescent properties.This approach uses a photosensitizer that can absorb the h-line UV light and transfer the energy to activate bisazide-based crosslinkers via Dexter energy transfer.Uniform,high-resolution(smallest feature size,2μm),and full-color patterns of red,green,and blue QD layers can be achieved.The patterned QD layers maintain up to~90%of their original photoluminescent quantum yields,comparing favorably with those(<60%)of QDs patterned without photosensitizers.We further extended the strategy to the direct three-dimensional(3D)printing of QDs.This photosensitizerassisted approach offers a new way for direct two-dimensional(2D)photopatterning and 3D printing of colloidal QDs,with implications in building high-performance QD optoelectronic devices.展开更多
基金supported by the National Natural Science Foundation of China(No.22274087)(H.Z.)Tsinghua University Dushi Program(H.Z.)the National Key Research and Development Program of China(No.2022YFB3204100)(T.-L.R.).
文摘Metal halide-based perovskites,with their exceptional photoelectric conversion efficiency,are promising materials for photodetectors and image sensors.Achieving high-definition optical imaging requires not only high-quality perovskite materials but also effective patterning methods.Here,we show the fabrication of pixelated photodetector arrays through a two-step process:(1)direct optical patterning of CsPbBr_(3) perovskite nanocrystal films using ligand cross-linkers,and(2)post-patterning ligand-exchange process.The direct optical patterning achieves high-resolution(≈2μm in pixel sizes),uniform CsPbBr_(3)nanocrystal film patterns over 2-inch wafers.The ligand-exchange process replaces the long hydrocarbon ligands and cross-linkers with compact ionic ligands,which enhance the charge transport efficacy without compromising the quality of the patterned films.Consequently,the patterned photodetectors,in the photoconductor configuration,show responsivity(0.11 A·W^(-1))and specific detectivity(1.81×10^(11)Jones)on par with their non-patterned counterparts.These features permit the creation of pixelated photodetector arrays that minimize the charge-sharing crosstalk effect and enable improved imaging capabilities.This work shows a promising approach in building high-performance perovskite image sensors.
基金supported by National Key Research and Development Program of China(No.2022YFB3602805)(H.Z.)the National Natural Science Foundation of China(No.22274087)(H.Z.)Tsinghua University Dushi Program(H.Z.).
文摘Direct photopatterning is a powerful strategy for patterning colloidal quantum dots(QDs)for their integration in various electronic and optoelectronic devices.However,ultraviolet(UV)exposure required for QD patterning,especially those with short wavelength(e.g.,deep UV light),can degrade the photo-,and electroluminescence,and other properties of patterned QDs.Here we develop a photosensitizer-assisted approach for direct photopatterning of QDs with h-line(centered at 405 nm)UV light and better preservation of their luminescent properties.This approach uses a photosensitizer that can absorb the h-line UV light and transfer the energy to activate bisazide-based crosslinkers via Dexter energy transfer.Uniform,high-resolution(smallest feature size,2μm),and full-color patterns of red,green,and blue QD layers can be achieved.The patterned QD layers maintain up to~90%of their original photoluminescent quantum yields,comparing favorably with those(<60%)of QDs patterned without photosensitizers.We further extended the strategy to the direct three-dimensional(3D)printing of QDs.This photosensitizerassisted approach offers a new way for direct two-dimensional(2D)photopatterning and 3D printing of colloidal QDs,with implications in building high-performance QD optoelectronic devices.
