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Abstract Thermally evaporated C60 is a near-ubiquitous electron transport layer in state-of-the-art p–i–n perovskite-based solar cells. As perovskite photovoltaic technologies are moving toward industrialization, batch-to-batch reproducibility of device performances becomes crucial. Here, we show that commercial as-received (99.75% pure) C60 source materials may coalesce during repeated thermal evaporation processes, jeopardizing such reproducibility. We find that the coalescence is due to oxygen present in the initial source powder and leads to the formation of deep states within the perovskite bandgap, resulting in a systematic decrease in solar cell performance. However, further purification (through sublimation) of the C60 to 99.95% before evaporation is found to hinder coalescence, with the associated solar cell performances being fully reproducible after repeated processing. We verify the universality of this behavior on perovskite/silicon tandem solar cells by demonstrating their open-circuit voltages and fill factors to remain at 1950 mV and 81% respectively, over eight repeated processes using the same sublimed C60 source material. Notably, one of these cells achieved a certified power conversion efficiency of 30.9%. These findings provide insights crucial for the advancement of perovskite photovoltaic technologies towards scaled production with high process yield.

Multimodal x-ray microscopy is key to assessing the property-functionality relationships of semiconductor devices with the utmost sensitivity and spatial resolution. Here, we report on a novel setup—the “Analyzer of X-ray excited Optical Luminescence Offering Temporal and spectraL resolution” (AXOLOTL)—and demonstrate its use by investigating a series of triple-cation mixed-halide perovskite solar cells (PSCs) with varying Cs content. These PSCs exhibit spatially varying performance and are thus ideally probed by multimodal x-ray microscopy to elucidate the origin of the performance variations. Specifically, our nanoscale characterization of the wrinkled perovskite photoabsorber unveils a segregation of I and Br, which is accompanied by a narrowed band gap and an increased charge-carrier lifetime in thick absorber areas. Overall, we demonstrate with this technique the spatial correlation of compositional inhomogeneities, topography, electrical performance, and optical performance, which is of highest interest for identifying loss mechanisms at the nanoscale in high-performance electronic device development, including solar cells.

Metal-halide perovskite based tandem solar cells are appealing but making a high efficiency device is not trivial. Here Chen et al. increase the carrier collection in the perovskite layer and largely enhance the efficiency in tandem cells when combined with colloidal quantum dot or silicon layers.

Light-ray tracing (RT) and the transfer matrix method (TMM) allow detailed optical simulation of single-junction silicon and perovskite solar cells, which critically aids device design towards record performance. However, their accuracy is compromised when simulating monolithic perovskite/silicon tandem devices built from textured silicon substrates, due to the resulting complex top-cell morphologies. The associated front surfaces of such tandem devices are typically either roughly conformal to the textured silicon underneath (for thermally evaporated or hybrid-deposited perovskites) or flattened (for solution-processed perovskites). Here, we develop accurate optical models for each configuration. For the conformal-like morphology, we apply a texture-on-texture model to accommodate for local imperfect conformalities. Contrastingly, for the flattened morphology, we develop a multi-subcell model to solve the limitation that films must be conformal in one-step RT + TMM simulations. We verify our models with experimental light absorption and quantum efficiency data for photovoltaic cells and modules in both morphological configurations and identify primary sources of parasitic light absorption. Finally, we extend our simulations to module-scale optics and find that textured module glass can effectively suppress photon escape for both tandem-device morphologies, improving their module performance.

Slot‐die coating is highly promising for scaled deposition of metal halide perovskite thin films. However, the power conversion efficiencies (PCEs) of slot‐die‐prepared perovskite solar cells (PSCs) still lag behind their spin‐casted counterparts. To resolve this issue, the crystal size and quality of slot‐die‐coated methylammonium lead triiodide (MAPbI3) perovskite films are dramatically improved via additive engineering using potassium thiocyanate (KSCN). The modified micrometer‐thick films have an average grain size of ≈11 μm and charge‐carrier parameters that are comparable with single‐crystal perovskites, such as a 1.89 μs lifetime, 136.65 ± 31.52 cm2 V−1 s−1 mobility, and 25.15 ± 3.55 μm diffusion length. Exploiting these enhanced properties, planar inverted PSCs with negligible hysteresis are fabricated and an average and a maximum PCE of 20.14% and 21.38%, respectively, are achieved which are among the highest reported values for slot‐die‐coated PSCs. Notably, our devices have a narrow PCE distribution along the slot‐die coating axis, highlighting slot‐die coating's promise to fabricate large‐scale, high‐performance PSCs.

Bu araştırmada, akademik tartışma modelinin 8. sınıf öğrencilerinin konuşma kaygılarına ve sözlü anlatım öz yeterlik algılarına etkisini incelemek amaçlanmıştır. Araştırmada, karma araştırma yöntem desenlerinden biri olan açımlayıcı sıralı desen kullanılmıştır. Bu bağlamda araştırmanın nicel boyutunda, “ön-test ve son-test kontrol gruplu” yarı deneysel desene; nitel boyutunda ise olgubilim desenine başvurulmuştur. Araştırmanın çalışma grubunu 49 öğrenci oluşturmaktadır. Bu öğrencilerden 24’ü deney grubunda, 25’i ise kontrol grubunda yer almaktadır. Araştırmanın nicel verileri, Gündüz (2020) tarafından geliştirilen “Konuşma Kaygısı Ölçeği” ve Demir (2020) tarafından geliştirilen “Sözlü Anlatım Öz Yeterlik Algısı Ölçeği” ile; nitel verileri ise araştırmacılar tarafından hazırlanan “Yarı Yapılandırılmış Görüşme Formu” ile toplanmıştır. Araştırmanın nicel veri analizinde, SPSS 20 analiz programı kullanılarak t-Testi ve iki yönlü ANOVA yapılmış; nitel veri analizinde ise NVivo 12 analiz programına başvurulmuştur. Araştırmanın sonuçlarına göre akademik tartışma modeliyle ders işlenen deney grubu öğrencilerinin, mevcut programla ders işlenen kontrol grubu öğrencilerine göre konuşma kaygılarının anlamlı derecede düştüğü, sözlü anlatım öz yeterlik algılarının ise anlamlı derecede arttığı gözlemlenmiştir. Ayrıca öğrencilerle yapılan görüşmeler sonucunda öğrenciler, bu tartışma modeliyle işlenen derslerden sonra konuşma özgüvenlerinin arttığını, konuşma kaygılarının düştüğünü, daha güçlü iletişim kurabildiklerini, birbirlerine daha saygılı olduklarını, etkili konuşabildiklerini belirtmişlerdir.

Bu araştırmanın amacı, ortaokul 6. sınıf öğrencilerinin Ömer Seyfettin’in And adlı öyküsünde yer alan şiddet olgusu hakkındaki görüşlerini tespit etmektir. Araştırma, Tuşba Kaymakamlık makamından araştırma izni alındıktan sonra 2021 yılı Ocak ayında gerçekleştirilmiştir. Araştırmanın örneklemini, Van ili Tuşba ilçesine bağlı İsmail Hakkı Tonguç Ortaokulu 6-A sınıfında öğrenim gören 22 öğrenci oluşturmaktadır. Araştırmada nitel araştırma desenlerinden fenomenoloji (olgubilim) kullanılmıştır. Verilerin toplanmasında uzman görüşü alınarak geliştirilen ve açık uçlu sorulardan oluşan yarı yapılandırılmış görüşme formu kullanılmış, verilerin çözümlenmesinde ise içerik analizi yöntemine başvurulmuştur. Araştırma sonucunda öğrencilerin eserde yer alan şiddet sahnelerini beğenmedikleri, şiddet içeren bölümlerden etkilendikleri, bu bölümleri eserden çıkarmak istedikleri tespit edilmiştir.

Looking at the scale of our country, the emergency service units, it is observed that the problems are not sufficiently taken into consideration and the unforeseen planning is made without considering the priorities of the personnel. It is an undeniable fact that this process causes disadvantages in terms of time, energy, economy, etc. and therefore decreases the work efficiency of health personnel. According to two studies conducted in the United States, unqualified emergency department designs represent a major obstacle to patient care of emergency personnel. On the other hand, in another study, it was stated that the correctly designed emergency department provides faster patient care and reduces the loss of labor of the personnel of the unit due to the deficiencies of the architectural structure. For this reason, it is important to question how health services are affected by the design of emergency rooms through the existing examples. In this context, the action areas and circulation areas of Trabzon 'Fatih State Hospital' and 'Kanuni Education and Research Hospital' emergency services units, which were selected as the study area, were examined in this context. For this purpose, data were gathered with 'Interview with personnel' and 'Space Syntax' techniques and the findings were compared with each other. As a result, it has been seen that the basic assumption of the study stating that handling spatial organization not according to the priorities of healthcare crew, that activity areas do not establish correct relations with each other, that the equipment placement does not sufficiently support the basic activity of the space negatively affect the service quality in both activity areas and also in circulation areas is supported.