Recent Progresses in Perovskite Solar Cells

Perovskite solar cell (PSC) can be regarded as a continuation of dye sensitized solar cell (DSSC) in terms of the sensitization phenomena that occurred in the functioning molecules. In 2012, a breakthrough propose has been made for the sensitization of PSCs, in which a solid‐state structure is offered as an equivalent sensitizer used in DSSC. The power conversion efficiency (PCE) of those solid‐state cells reached about twofold of its initial value during the past several years. Immediately after, the researchers followed this propose worldwide. They have introduced an improved efficiency of as much as 20%, which was originally started from its initial value of 4%, just in 4 years. Thus, the new concept, solid perovskite molecules, has eliminated the need for the liquid electrolyte in DSSC while still carrying the advantages of organic solar cells (OSCs). Therefore, the distinctive material of PSC—the organometallic halide molecules (also known as OMH or organic‐inorganic trihalides)—inclined an unexpected reputation for solar cell (SC) researches. Hence, it seems that we will witness a new age for solar conversion devices depending on the recent hopeful progresses on PSCs. The high rate of photovoltaic (PV) conversion capacity in PSC is generally expressed by the basic properties possessed by the organic‐inorganic perovskite crystal, such as better optical properties and well diffused charges along huge distances during the charge transport. In addition, a low temperature processing is applicable during its production. Moreover, the perovskite layer provides a tunable band gap. Therefore, depending on better developments on designed molecules, PSC may gain extreme performances compared to the other competitors, such as OSC or DSSC devices. This chapter starts with a general discussion on the need for an affordable clean energy conversion device that is urgent for the future of humanity, due to publicly well‐known global warming issue. In Section 2, basic properties of PSC are mentioned together with their structure and working principles. Section 3 continues with an overview on organometallic perovskite molecules after a brief introductory history is presented. The absorption and band gap properties are also discussed. Since most perovskite materials need a hole transporting material (HTMs) within the PSC, the kinds of HTMs that are designed for PSCs are described in Section 3. The rendering of long‐term stabilization has special importance for PSCs since the instability issue remained idle in spite of those recent increased efficiency values attained by various research groups. Therefore, the stability issues are discussed in a separate part in Section 4. We finally close the chapter discussing the challenges and opportunities relying on the chapter content. We note that the recent investigations on PSCs have special importance for its large‐scale realization in order to make them ready for the photovoltaic industry of the future. Hence, there are various announced meetings focusing on its mass production due to the unexpected sharp rise of the perovskite efficiency in the last 6 years. Hence, all the new cutting‐edge scientific findings are also dealt with commercialization issues now, in order to attain the desired low cost fabrication, including the yield of high purity and the formation of smooth films during the continual manufacture of perovskite layers

Effect of Fe doping on the CO gas sensing of functional calixarene molecules measured with quartz crystal microbalance technique

WOS: 000354131200061This article presents comprehensive studies of carbon monoxide (CO) responses of bare and iron doped six calix[4]arene derivatives substituted with various functional groups based on quartz crystal microbalance (QCM) technique. The functional groups in calixarene molecules were chosen to increase the affinity towards CO. The sensitive films were prepared by using drop casting method on a QCM gold electrode with resonance frequency of 7.995 MHz. The responses of bare and Fe doped calixarene molecules were investigated in details. Our QCM results showed that although both bare and Fe doped calixarene molecules are very sensitive to CO gas and Fe doped calixarene molecules have higher affinity to CO about 27.88 times greater than bare are. Therefore, these results open an approach to create new materials for the gas sensing applications. (C) 2015 Elsevier B.V. All rights reserved.TUBITAK (Turkish Scientific Association)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG 109T240]This research was supported by TUBITAK (Turkish Scientific Association) under project number TBAG 109T240. We are grateful to Dr. Mustafa Can for help with fruitful discussions about the results of organic molecules