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.
|공지||<12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생||2016.11.28||1058371|
|602||<11/23(Fri.) 11:00am>Barrier-bound States in Flat-band Systems||2018.11.19||52434|
|601||<2/8(Fri) 2:00pm ~ > 5d SCFTs and Type IIB 5-brane webs||2019.02.01||52799|
|600||<11/21(Wed.) 2:00pm>Origin of Hawking Radiation||2018.11.20||53090|
|599||<April 25(Mon) 16:30> Neutron Recoil Polarization in Low‐energy Photodisintegration of the Deuteron||2016.04.25||53215|
|598||<8/23(Thu.) 2:00pm>What will we do with near-term quantum computers?||2018.08.17||53311|
|597||<June 1(Wed.) 4:30 PM> 중력으로 강한 핵력 이해하기||2016.05.26||53475|
|596||<Nov. 9(Wed.) 4:30 PM> 20-nm resolution imaging of brain circuitry by next-generation expansion microscopy||2016.11.02||53786|
|595||<May. 18(Wed.) 4:30 PM> Search for Hidden Neutrinos at the High Energy Frontier||2016.05.23||53793|
|594||<Mar. 15(Wed.) 4:30 PM>반도체 Fab Process와 물리학 전공자||2017.03.14||53831|
|593||<Dec. 14(Wed.) 4:30 PM>중력과 양자 얽힘 (tentative)||2016.12.07||53832|
|592||<May. 4(Wed.) 4:30 PM> 플라즈마를 이용한 표면처리 기술||2016.04.27||54116|
|591||<April. 27(Wed.) 4:30 PM> 로봇과 함께 살아갈 미래||2016.04.22||54186|
|590||<Mar.20(Wed.)> Connecting Thermoelectricity and Superconductivity by Pressure Bridge||2019.03.13||54340|
|589||<Dec.13(Wed.) 4:30 PM>기본에 충실하고 새로움에 도전한다 - 자율주행자동차의 핵심 기술들 –||2017.12.07||54460|
|588||<June 8(Wed.) 4:30 PM> 세계와 우리나라 우주개발 도전||2016.06.01||54565|
|587||<12/2(Fri.) 14:00>Overview of HIMAC facility||2016.12.01||54585|
|586||<Nov. 2(Wed.) 4:30 PM> 현대 우주론 이론과 관찰 (Theories and observations of modern cosmology)||2016.10.19||54728|
|585||<8/26(Mon) 14:00 ~ >Constructing viable models of bouncing scenarios||2019.08.20||55239|
|584||<Oct.7(Wed.)>Organic Photodiode for Image Sensor||2020.09.24||55265|
|583||<May 10(Wed.) 4:30 PM>Trend and beyond of semiconductor technology (반도체 미세화 및 신기술 동향)||2017.05.04||55581|