Diminishing surface defect states in perovskite nancx^rystals is a highly challenging subject for enhancing optoelectronic device performance.We synthesized organic/inorganic lead-halide perovskite MAPbBr3(MA=methylam...Diminishing surface defect states in perovskite nancx^rystals is a highly challenging subject for enhancing optoelectronic device performance.We synthesized organic/inorganic lead-halide perovskite MAPbBr3(MA=methylammonium)clusters comprising nanocrystals with diameters ranging between 20 and 30 nm and characterized an enhanced photoluminescence(PL)quantum yield(as much as^7 times)by encapsulating the MAPbBr3 with graphene(Gr).The optical properties of MAPbBr3 and Gr/MAPbBr3 were investigated by temperature-dependent micro-PL and time-resolved PL measurements.Density functional theory calculations show that the surface defect states in MAPbBr3 are removed and the optical band gap is reduced by a 0.15 eV by encapsulation with graphene due to partial restoration of lattice distortions.展开更多
Inorganic perovskite lasers are of particular interest,with much recent work focusing on Fabry-P6rot cavity-forming nanowires.We demonstrate the direct observation of lasing from transverse electromagnetic(TEM)modes w...Inorganic perovskite lasers are of particular interest,with much recent work focusing on Fabry-P6rot cavity-forming nanowires.We demonstrate the direct observation of lasing from transverse electromagnetic(TEM)modes with a long coherence time-9.5ps in coupled CsPbBr_(3) quantum dots,which dispense with an external cavity resonator and show how the wavelength of the modes can be controlled via two independent tuning-mechanisms.Controlling the pump power allowed us tofine-tune the TEM mode structure to the emission wavelength,thus providing a degree of control over the properties of the lasing signal.The temperature-tuning provided an additional degree of control over the wavelength of the lasing peak,importantly,maintained a constant full width at half maximum(FWHM)over the entire tuning range without mode-hopping.展开更多
SnO_(2) electron transport layer(ETL)has been spotlighted with its excellent electron extraction and stability over TiO_(2) ETL for perovskite solar cells(PSCs),rapidly approaching the highest power conversion efficie...SnO_(2) electron transport layer(ETL)has been spotlighted with its excellent electron extraction and stability over TiO_(2) ETL for perovskite solar cells(PSCs),rapidly approaching the highest power conversion efficiency.Thus,how to boost the performance of ETL is of utmost importance and of urgent need in developing more efficient PSCs.展开更多
基金This work was supported by Basic Science Research Program and National H onor Scientist Program through the National Research Foundation of Korea(NRF)(Nos.2010-0020414,2015R1D1A1A01058332,2018R1D1A1B07043676,2019R1A4A1029237).K.S.K.acknowledges the support from KISTI(Nos.KSC-2018-CRE-0077,KSC-2018-CHA-0057).C.W.M.acknowledges the support from KISTI(Nos.KSC-2018-CRE-0071,KSC-2019-CRE-0139,KSC-2019-CRE-0248).
文摘Diminishing surface defect states in perovskite nancx^rystals is a highly challenging subject for enhancing optoelectronic device performance.We synthesized organic/inorganic lead-halide perovskite MAPbBr3(MA=methylammonium)clusters comprising nanocrystals with diameters ranging between 20 and 30 nm and characterized an enhanced photoluminescence(PL)quantum yield(as much as^7 times)by encapsulating the MAPbBr3 with graphene(Gr).The optical properties of MAPbBr3 and Gr/MAPbBr3 were investigated by temperature-dependent micro-PL and time-resolved PL measurements.Density functional theory calculations show that the surface defect states in MAPbBr3 are removed and the optical band gap is reduced by a 0.15 eV by encapsulation with graphene due to partial restoration of lattice distortions.
基金Basic Science Research Program and National Honor Scientist Program through the National Research Foundation of Korea(NRF)(Nos.2010-0020414,2018R1D1A1B07043676).T.F.acknowledges support from the Centre for Quantum Technologies,National University of Singapore.
文摘Inorganic perovskite lasers are of particular interest,with much recent work focusing on Fabry-P6rot cavity-forming nanowires.We demonstrate the direct observation of lasing from transverse electromagnetic(TEM)modes with a long coherence time-9.5ps in coupled CsPbBr_(3) quantum dots,which dispense with an external cavity resonator and show how the wavelength of the modes can be controlled via two independent tuning-mechanisms.Controlling the pump power allowed us tofine-tune the TEM mode structure to the emission wavelength,thus providing a degree of control over the properties of the lasing signal.The temperature-tuning provided an additional degree of control over the wavelength of the lasing peak,importantly,maintained a constant full width at half maximum(FWHM)over the entire tuning range without mode-hopping.
基金This work was supported by NRF(National Honor Scientist Program:2010-0020414)K.S.K.acknowledges the support from KISTI(KSC-2018-CHA-0057,KSC-2018-CRE-0077,KSC-2019-CRE-0103,KSC-2019-CRE-0253,KSC-2020-CRE-0049)+2 种基金C.W.M.acknowledges the support from KISTI(KSC-2018-CRE-0071,KSC-2019-CRE-0139,KSC-2019-CRE-0248)J.K.acknowledges the support from KISTI(KSC-2018-CRE-0055,KSC-2019-CRE-0064,KSC-2019-CRE-0244)J.K thanks to Dr.Sung Bum Kang for valuable discussions.
文摘SnO_(2) electron transport layer(ETL)has been spotlighted with its excellent electron extraction and stability over TiO_(2) ETL for perovskite solar cells(PSCs),rapidly approaching the highest power conversion efficiency.Thus,how to boost the performance of ETL is of utmost importance and of urgent need in developing more efficient PSCs.
