The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and s...The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.展开更多
Organic thermoelectric generators(TEGs)are flexible and lightweight,but they often have high electrical resistance,poor output power,and low mechanical durability,because of which their thermoelectric performance is p...Organic thermoelectric generators(TEGs)are flexible and lightweight,but they often have high electrical resistance,poor output power,and low mechanical durability,because of which their thermoelectric performance is poor.We used a facile and rapid solvent evaporation process to prepare a robust carbon nanotube/Bi0.45Sb1.55Te3(CNT/BST)foam with a high thermoelectric figure of merit(zT).The BST sub-micronparticles effectively create an electrically conductive network within the three-dimensional porous CNT foam to greatly improve the electrical conductivity and the Seebeck coefficient and reinforce the mechanical strength of the composite against applied stresses.The CNT/BST foam had a zT value of 7.8×10^(−3)at 300 K,which was 5.7 times higher than that of pristine CNT foam.We used the CNT/BST foam to fabricate a flexible TEG with an internal resistance of 12.3Ωand an output power of 15.7μW at a temperature difference of 21.8 K.The flexible TEG showed excellent stability and durability even after 10,000 bending cycles.Finally,we demonstrate the shapeability of the CNT/BST foam by fabricating a concave TEG with conformal contact on the surface of a cylindrical glass tube,which suggests its practical applicability as a thermal sensor.展开更多
Ultra-flexible organic photovoltaics(OPVs)are promising candidates for next-generation power sources owing to their low weight,transparency,and flexibility.However,obtaining ultra-flexibility under extreme repetitive ...Ultra-flexible organic photovoltaics(OPVs)are promising candidates for next-generation power sources owing to their low weight,transparency,and flexibility.However,obtaining ultra-flexibility under extreme repetitive mechanical stress while maintaining optical transparency remains challenging because of the intrinsic brittleness of transparent electrodes.Here,we introduce straindurable ultra-flexible semitransparent OPVs with a thickness below 2μm.The conformal surface coverage of nanoscale thin metal electrodes(<10 nm)is achieved,resulting in extremely low flexural rigidity and high strain durability.In-depth optical and electrical analyses on ultrathin metal electrodes showed that the devices maintain over 73%of their initial efficiency after 1000 cycles of repetitive compression and release at 66%compressive strain,and the average visible light transmittances remain higher than 30%.To our knowledge,this is the first systematical study on mechanical behaviors of strain-durable ultra-flexible ST-OPVs through precise adjustment of each ultrathin electrode thickness toward the emergence of next-generation flexible power sources.展开更多
基金granted by the Korea Research Institute of Chemical Technology(KRICT)of the Republic of Korea(No.2422-10)the National Research Foundation(NRF)(NRF-2021R1C1C2007445 and RS-2023-00280495)of Republic of Korea.
文摘The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.
文摘Organic thermoelectric generators(TEGs)are flexible and lightweight,but they often have high electrical resistance,poor output power,and low mechanical durability,because of which their thermoelectric performance is poor.We used a facile and rapid solvent evaporation process to prepare a robust carbon nanotube/Bi0.45Sb1.55Te3(CNT/BST)foam with a high thermoelectric figure of merit(zT).The BST sub-micronparticles effectively create an electrically conductive network within the three-dimensional porous CNT foam to greatly improve the electrical conductivity and the Seebeck coefficient and reinforce the mechanical strength of the composite against applied stresses.The CNT/BST foam had a zT value of 7.8×10^(−3)at 300 K,which was 5.7 times higher than that of pristine CNT foam.We used the CNT/BST foam to fabricate a flexible TEG with an internal resistance of 12.3Ωand an output power of 15.7μW at a temperature difference of 21.8 K.The flexible TEG showed excellent stability and durability even after 10,000 bending cycles.Finally,we demonstrate the shapeability of the CNT/BST foam by fabricating a concave TEG with conformal contact on the surface of a cylindrical glass tube,which suggests its practical applicability as a thermal sensor.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00213089)supported by the Technology Innovation Program(Grant No.RS-2022-00154781,Development of large-area wafer-level flexible/stretchable hybrid sensor platform technology for form factor-free highly integrated convergence sensor)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)+1 种基金supported by the MSIT,Korea,under the ITRC(Information Technology Research Center)support program(Grant No.IITP-2023-2020-0-01461)supervised by the IITP(Institute for Information&communications Technology Planning&Evaluation)supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2021K1A4A7A03093851).
文摘Ultra-flexible organic photovoltaics(OPVs)are promising candidates for next-generation power sources owing to their low weight,transparency,and flexibility.However,obtaining ultra-flexibility under extreme repetitive mechanical stress while maintaining optical transparency remains challenging because of the intrinsic brittleness of transparent electrodes.Here,we introduce straindurable ultra-flexible semitransparent OPVs with a thickness below 2μm.The conformal surface coverage of nanoscale thin metal electrodes(<10 nm)is achieved,resulting in extremely low flexural rigidity and high strain durability.In-depth optical and electrical analyses on ultrathin metal electrodes showed that the devices maintain over 73%of their initial efficiency after 1000 cycles of repetitive compression and release at 66%compressive strain,and the average visible light transmittances remain higher than 30%.To our knowledge,this is the first systematical study on mechanical behaviors of strain-durable ultra-flexible ST-OPVs through precise adjustment of each ultrathin electrode thickness toward the emergence of next-generation flexible power sources.
