Excellent Silicon Surface Passivation Achieved by Industrial Inductively Coupled Plasma Deposited Hydrogenated Intrinsic Amorphous Silicon Suboxide

We present an alternative method of depositing a high-quality passivation film for heterojunction silicon wafer solar cells, in this paper. The deposition of hydrogenated intrinsic amorphous silicon suboxide is accomplished by decomposing hydrogen, silane, and carbon dioxide in an industrial remote inductively coupled plasma platform. Through the investigation on CO2 partial pressure and process temperature, excellent surface passivation quality and optical properties are achieved. It is found that the hydrogen content in the film is much higher than what is commonly reported in intrinsic amorphous silicon due to oxygen incorporation. The observed slow depletion of hydrogen with increasing temperature greatly enhances its process window as well. The effective lifetime of symmetrically passivated samples under the optimal condition exceeds 4.7 ms on planar n-type Czochralski silicon wafers with a resistivity of 1 Ωcm, which is equivalent to an effective surface recombination velocity of less than 1.7 cms−1 and an implied open-circuit voltage (Voc) of 741 mV. A comparison with several high quality passivation schemes for solar cells reveals that the developed inductively coupled plasma deposited films show excellent passivation quality. The excellent optical property and resistance to degradation make it an excellent substitute for industrial heterojunction silicon solar cell production

Mitigation of Open‐Circuit Voltage Losses in Perovskite Solar Cells Processed over Micrometer‐Sized‐Textured Si Substrates

The recent development of solution-processed perovskite thin films over micrometer-sized textured silicon bottom solar cells enables tandem solar cells with power conversion efficiencies > 30%. Next to improved light harvesting, textured silicon wafers are the industrial standard. To achieve high performance, the open-circuit voltage losses that occur when fabricating perovskite solar cells over such textures need to be mitigated. This study provides a practical guideline to discriminate and address the voltage losses at the interfaces as well as in the bulk of solution-processed double cation perovskite thin films using photoluminescence quantum yield measurements. Furthermore, the origin of these losses is investigated via morphological, microstructural, and compositional analysis and present possible mitigation strategies. The guideline will be beneficial for scientists working on randomly textured surfaces and provides a deeper understanding on this timely research topic

Synthese, Charakterisierung und Eigenschaften von Hauptgruppenmetallkomplexen des Tetraphenyl- und Tetrakis(4-sulfonatophenyl)porphyrins

Neue waserlösliche Porphyrinkomplexe des Tetrakis(4-sulfonato)phenylporphyrins mit mit Zentralmetallen der III. IV. und V. Hauptgruppe wurden synthetisiert und mit ihren analogen, lipophilen Komplexen des Tetraphenylporphyrins verglichen, die ebenfalls während dieser Arbeit dargestellt wurden. Neue Strategien der Synthese und Aufarbeitung wurden entwickelt. Die neuen Komplexe wurden mit Hilfe der UV/Vis-, Fluoreszenz, IR-, NMR-Spektroskopie, Massenspektrometrie und Elementaranalytik charakterisiert. Fluoreszenzausbeuten der Metallporphyrinate wurden bestimmt. Reinheitsuntersuchungen der wasserlöslichen Porphyrinate wurden mit Hilfe der Gelelektrophorese durchgeführt oder mit Dünnschichtchromatographie im Fall der lipophilen Komplexe. Die Redoxpotentiale der Metallporphyrinate wurden mit Hilfe der Cyclischen Voltammetrie bestimmt. Heteroaggregationsversuche zwischen den wasserlöslichen Komplexen und einem Cobaltporphyrazin wurden durchgeführt. Ladungstransfer- und Bestrahlungsexperimente der Heteroaggregate wurden durchgeführt in Kooperation mit dem Commissariat à lénergie atomique in Saclay. Preparative HPLC-Experimente zur Reinigung des Tetrakis(4-sulfonato)phenylporphyrins und zur Isolierung und Charakterisierung eines Stellungsisomers, das mit Hilfe der analyischen HPLC beobachtet wurde, wurden durchgeführt

Efficient Light Harvesting in Thick Perovskite Solar Cells Processed on Industry-Applicable Random Pyramidal Textures

Light management is key to high-performance solar cells, particularly to monolithic perovskite/Si tandem solar cells and in real field applications. Random pyramidal textures of commercial Si solar cells (height ∼2–5 μm) allow for efficient light harvesting; however, solution processing of conventional perovskite thin films (thickness ∼0.5 μm) over these large textures exhibits bad coverage, resulting in shunting paths. In response to this challenge, we present high-efficiency perovskite solar cells (PSCs) processed on replicated industry-applicable random pyramidal textures with a smaller pyramid size of ∼1–2 μm. As a first step, we develop planar PSCs with close to micrometer thick perovskite absorber layers that maintain efficient charge carrier extraction by using a Lewis base additive and exhibit a power conversion efficiency of up to 18%. Employing these thick films in textured PSCs with inverted pyramids improves the light management as compared to the planar reference, with the AM 1.5G weighted reflectance being reduced from 9.9 to 5.2%. The reduced broadband reflectance in conjunction with enhanced light trapping increases the current generation by 7.7% relative, which corresponds to 87.3% of the maximum attainable short-circuit current density. In addition, we maintain a high fill factor and open-circuit voltage comparable to that of the planar reference PSC despite the increased surface area of the texture. Thereby, our champion textured PSC exhibits a stabilized power output of 18.7% at maximum power point tracking for 5 min. Finally, the textured PSCs also exhibit improved current generation for all angles of incidence, emphasizing their advantages at realistic irradiation conditions and for bifacial applications

Investigation of Wide Process Temperature Window for Amorphous Silicon Suboxide Thin-Film Passivation Deposited by Inductively Coupled PECVD

10.1109/JPHOTOV.2015.2397593IEEE Journal of Photovoltaics53705-71