Time-resolved spectroscopic study of photo-excited charge carrier dynamics in hematite (α-Fe2O3): Effect of re-growth treatment

Roles of Surface States in Cocatalyst-Loaded Hematite Photoanodes for Water Oxidation

“…This charging process on S1 and S2 was in equilibrium through electronic interaction. Since the lifetime of S2 was surprisingly long (in a second scale) compared with that of S1 (in 10 −3 ∼ 10 −1 s), 33 the capacitance of S1 needs to be much larger than that of S2 to trap more holes for water oxidation. However, since the lifetime of holes in S1 was relatively short, the hole transfer for water oxidation was severely competed by its recombination with electrons from conduction band.…”

A new strategy for monitoring the charge transfer from perovskite thin films to electron transport layers using a heterodyne transient grating technique

“…Because the wavelength of the pump light used in this study was 532 nm, we could guarantee that the observed signal solely originated from the excitation of the MAPbI 3 layer. In addition, based on the band alignment of MAPbI 3 /ZnO (Type-II heterojunction) 21,22,24 and the high sensitivity of the HD-TG method at the interface, [26][27][28][29][30][31] it is evident that the signal arising from the components in the ZnO layer, transferred from MAPbI 3 , was monitored.…”

“…Therefore, in order to overcome the above-mentioned drawbacks of the femtosecond time-resolved spectroscopic techniques, in this study, we fabricated MAPbI 3 and MAPbI 3 /ZnO films as shown in Fig. 1A and B, respectively, and investigated the electron transfer between MAPbI 3 and ZnO using a heterodyne transient grating (HD-TG) method, which is one of the time-resolved spectroscopic techniques utilized for the investigation of the photo-excited charge carrier dynamics at the solid/ liquid interface, [26][27][28][29][30][31] by monitoring the surface trapped charge carriers in the ZnO layer, originating from MAPbI 3 . The signal of the HD-TG response could be amplified by mixing a large reference field (0th order) with a weak signal field and the high sensitivity for the observation of the weak signal originating from such as the small number of the surface trapped charge carriers could be achieved by the linearization.…”

Investigation of The Effects of Ni-Doping on The Structural Properties of Fe2O3

“…İlginç optoelektronik özelliklere sahip kompleks elektronik yapıların eşliğinde güçlü elektron-elektron etkileşimleri ve elektron-foton rezonansları sergiler [1]. Hematit, doğal bolluğu [3,4], düşük maliyeti [3][4][5][6][7][8], çevre dostu yapısı [3,4,8], toksik olmaması [7], düşük bant aralığı (2,1-2,3eV) [6], korozyona karşı yüksek direnci [6,7], yüksek teorik özgül kapasitesi [4], yüksek görünür ışık soğurma verimi [5], yüksek foto kararlılığı [5] gibi üstün özellikleri nedeni ile geniş bir kullanım alanına sahiptir. Biyokimyasal özellikleri, özellikle toksikoloji olmak üzere birçok bölümde incelenmiştir [9].…”

“…Bu avantajlı özelliklerin yanında, zayıf iletkenlik, kısa elektron-hol ömrü ve zayıf yük taşıyıcı transfer/taşıma verimliliği gibi sınırlayıcı dezavantajlı özellikleri de mevcuttur [5,10]. Morfoloji mühendisliği ve katkılama, elektron-hol çiftlerinin yüzeye taşınmaları için daha kısa yollar sağlayarak ve yük rekombinasyonunu engelleyerek bu sorunların ele alınmasında etkili olmuştur [3].…”