korean english


Home > 게시판 > 세미나

이번 학기 콜로퀴움은 학교의 권고를 따라, 사회적 거리두기 단계와 연계하여 온라인 혹은 오프라인(온라인 방송 병행)으로 운영될 예정입니다.

일곱번째 강연에는 충남대학교 에너지과학과 임종철 교수님을 모시고 콜로퀴움을 개최하오니, 학과 구성원 여러분의 많은 참여를 부탁 드립니다.

코로나19 확산방지를 위해 다과는 제공하지 않습니다.


1. Title: Progresses in Elucidating the Optoelectronic Properties of Perovskite Semiconductor

2. Speaker: 임  종  철 
교수님 (충남대학교 에너지과학과)

3. Date & Time: Nov. 4. (Wed.) 2020.  4:30 PM

4. Place: Natural Science 1,  Room No. 31214

5. Abstract: Many different standard spectroscopic measurements have been employed for precise quantification of key optoelectronic properties (i.e. light absorption strength, bandgap, charge carrier lifetime and radiative efficiency) of metal halide perovskites. It has been greatly beneficial for rapidly advancing the quality of perovskite thin films and ensuing solar cell efficiency.
In contrast, charge carrier mobility (ratio between the drift velocity and the electric field), has proven to be much more challenging to quantify. In addition to mobile electrons and holes, the mobile ions in metal halide perovskites redistribute under an applied electric field. It negates many benefits of standard spectroscopic techniques to quantify mobility, such as nanosecond to millisecond transient methods, time-of-flight and space charge limited current measurements. Indeed, an accurate estimation of charge carrier density is hindered by early-time recombination, the branching ratio of excitons to free-carriers and sensitivity to short-range conductivity unlikely influenced by scattering events at grain boundaries and charge trapping. It is, therefore particularly more important to understand the long-range charge transport within the metal halide perovskite for optimisation of operating devices, where the charges have to travel over on the order of microns, and if these properties change in different carrier density regimes, or through different methods of processing the films.
Here the present talk introduces a new methodology and also highlights an advanced optical and electrical methodologies: Photoinduced transmission and reflection (PITR), Transient photo-conductivity (TPC) and Pulsed-voltage space charge limited current (PV-SCLC). With these methods, we accurately estimated the internal free-carrier density during photo-excitation, accounting for both early-time recombination and exciton-to-free-carrier branching ratios to determine long-range charge carrier mobility in metal halide perovskite thin films and single crystals, to be invariant over many orders of magnitude of charge density. We also demonstrate that the processing method of perovskite layer has a strong influence on the long-range charge transport. We believe this study is the first accurate evaluation of photo-induced long-range mobility of metal halide perovskites, and therefore represents a new handle for future optimisation of perovskite solar cells and optoelectronic devices. Moreover, we expect our methodology to be especially useful for polycrystalline and nanostructured semiconductor materials, where the long-range mobility is expected to vary considerably in comparison to the short-range mobility, such as quantum dots, carbon materials, semiconducting organic molecules and metal oxides.

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1091480
78 <11/4>Plasmonic Properites of Metallic Nanostructures 2009.10.30 96945
77 <10/9> Smearing effect of membrane in plane-wave matrix model 2009.10.05 100432
76 <10/15> An Ideal Mean-Field Transition in a Driven Interacting System 2009.09.30 110288
75 <9/15> Resistance Switching Behavior of Epitaxially Grown NiO Thin Films 2009.09.07 166087
74 <8/11>Cooking up elements in the universe: Recent activities at HRIBF 2009.08.11 114292
73 <8/5>Brane superpotential via local Calabi-Yau spaces 2009.08.03 124263
72 <7/15> Experiment for Discoveries of Extrasolar Planets 2009.07.13 103734
71 <7/17> Atomic-scale polar oxide heterostructures: Growth and interfacial properties 2009.07.13 110273
70 <7/8> 신물질 고온초전도 초청강연 2009.06.26 90059
69 <6/17> Oscillating Fuzzy Sphere and M5/anti M5 configurations in ABJM model 2009.06.16 264684
68 <6/17> Molecular dynamics simulation to study amorphous structure of Ge2Sb2Te5 2009.06.03 88338
67 <6/18> Multiferroics: Magnetism-driven Ferroelectricity 2009.05.27 123249
66 <5/11>Emergent Geometry as Quantum Gravity 2009.05.07 102959
65 <4/30> Updates on warped brane inflation 2009.04.21 125724
64 <4/27> BPS Vortices in Non-relativistic M2-brane Chern-Simons-matter Theory 2009.04.21 81873
63 <4/21> Experimental and Observational Astrophysics in the Infrared Wavebands 2009.04.17 133012
62 <4/20> Chern-Simons gauge theories and M2 brane CFTs 2009.04.09 78055
61 <4/14> X-ray absorption fine structure analyses on amorphous oxide films 2009.04.06 131603
60 <3/26>A perturbative & non-perturbative test of ABJM model 2009.03.19 92578
59 <4/3> Spin-orbit coupling induced Mott insulating state 2009.03.13 96453