| 학회 | 한국재료학회 |
| 학술대회 | 2017년 가을 (11/15 ~ 11/17, 경주 현대호텔) |
| 권호 | 23권 2호 |
| 발표분야 | B. 나노화학/바이오 분과 |
| 제목 | Surface Engineering for Improved Stability of CH3NH3PbBr3 Perovskite Nanocrystals |
| 초록 | Organohalide lead perovskite nanoparticles (PNP) have shown a promising potential for their applications in optoelectronic devices (e.g. solar energy harvesting, piezoelectric energy generator, lighting, sensor for gas and chemical substances, polarity chemosensor, photodetectors, etc.) owing to their size- and composition-dependent optoelectronic properties. Despite extensive studies on their size dependent optical properties, a lack of knowledge on morphological transformation and stability issue limit a wide range of applications. We have prepared green-emitting CH3NH3PbBr3 perovskite NPs by previously reported ligand assisted reprecepitation (LARP) method and systematically investigated the stability of CH3NH3PbBr3 NPs in the solution, and found that these NPs suffer severe degrading resulting NP size and morphology deterioration, and reduced optical performance. We hypothesize a mechanism on the morphological transformation of PNPs after synthesis, which leads to dissolving nanocrystals and forming microscale rectangular grains mediated by the liquid phase, resulting in a reduction of photoluminescence within a few hours of aging. We terminated the liquid mediated transformation of PNPs by treatment of surface by alike amine–based surfactant along oleic acid leads to improved PNPs by several aspects. We first synthesized perovskite NPs at limited supply of initial materials to prevent particle aggregation and growth, and then added extra amount of alike surfactant containing solution. PL performance improved twice and maintains stabile at the level of 90 % of its initial value during two days of aging. The meantime the emission wavelength, FWHM, and absorption edge remain unchanged (at 500nm, 25nm, and 2.6meV, respectively) indicating that the particle growth is successfully terminated by surface treatment. Moreover, precise control of the precursor and surfactant contents suppresses particle growth, resulting in nearly monodisperse PNPs with a square shape (~20nm edge size), and thus improves the stability of PNP solution and PL performance. We investigated also the effect of molecular structure of surfactant on the NP stability and PL performance by employing various amine derivatives. |
| 저자 | Artavazd Kirakosyan, Seokjin Yun, Jiye Kim, Jihoon Choi |
| 소속 | Chungnam National Univ. |
| 키워드 | Perovskite; CH<SUB>3</SUB>NH<SUB>3</SUB>PbBr<SUB>3</SUB>; Quantum dot; luminescence; nanocrystal |
