logo

korean english

게시판

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 1079227
290 <11/5(수)> 안전한 사회를 위한 과학의 역할 2014.11.01 64187
289 <10/30> 광섬유 센서 2013.10.17 64700
288 <Dec.12(Wed.)> First-principles studies of complex oxides interfaces 2018.12.05 64939
287 <3/18(수) 오후4:30분> 시장리스크 관리(Market Risk Management) 소개 2015.03.11 64987
286 <4/8(수) 오후4:30분> 우라늄의 일생 2015.04.02 65376
285 <Oct. 12(Wed.) 4:30 PM> Silk as a biocompatible optical material 2016.10.05 65800
284 <10/15(수)> 첨단 과학 기술의 세계와 물리학의 위상 2014.10.08 66057
283 <Oct. 14(Wed.) 4:30 PM> 국방과학기술과 물리학 2015.10.07 66271
282 <10/2> What's the matter? 2013.09.26 66502
281 <9/24(수)> Design Principles of Cellular Networks 2014.09.18 66876
280 <10/1(수)> 초전도 양자컴퓨터 - Superconducting qubit and circuit QED 2014.09.26 67064
279 <4/3> 내 안의 파장을 바꿔라! 2013.03.29 67182
278 <May.1(Wed.)> Introduction of AMS Application 2019.04.24 67311
277 <12/11> Is Nature Natural? 2013.12.05 67462
276 <11/14> Next Generation LED 2012.11.08 67803
275 <3/13> Quantum computing using solid state nano-devices 2013.03.08 68285
274 <6/10(수) 오후4:30분> Closing in on the Axion Dark Matter hypothesis 2015.06.03 68329
273 <Oct.2(Wed.)> Fundamental physics with high-energy atmospheric and cosmic neutrinos today and in the future 2019.09.26 68496
272 <May. 11(Wed.) 4:30 PM> In-situ x-ray studies of functional oxides for energy systems 2016.05.23 68523
271 <9/17(수)> Reshaping Micro/Nanophotonics by Programmable Soft-Matter 2014.09.15 68747