Description
The project aims towards the realization of flexible photovoltaic solar cells with a level of conversion efficiency close to 20 %. These will be based on new phenomena - low cost fabrication technologies allowing recycling of the indoor light, all at a demonstrator level. These achievements can bring important energy savings in public spaces and reduced costs for photovoltaic systems designed for individual houses. The consortium strategy is including research for: (i) understanding and controlling the physical mechanisms in the investigated structures - theoretical and experimental studies; (ii) development of low cost technologies to be used for fabrication of flexible solar cells. The consortium has the expertise to tackle these problems and is composed of 6 partners, 3 from Romania (NIMP, UB and OPTOELECTRONICA 2001 SA) and 3 from donor states Iceland (UI and RU) and Norway (UiO), with the following roles in the project: NIMP-develop and characterize standard and flexible perovskite solar cells from solution-processed layers; UB- develop and characterize planar perovskite solar cells by vacuum evaporation; OPTOELECTRONICA 2001 SA -is a private company which will develop a demonstrator equipment for printing like technology for the final cell; UiO- Synthesis of alternative transparent conductive oxides, to replace the presently used FTO electrode in the solar cells, by chemical vapour deposition, atomic layer deposition, magnetron sputtering and ion implantation; UI- deposition of the electron transporter in the standard cells by sputtering and defect investigations of the structures developed within the consortium; RU - First-principles studies and atomistic models for the perovskite absorber in the cells. All the structures developed within the consortium will be investigated by the different techniques available at each partner site. The project will consolidate the cooperation between the partners and will offer new opportunities of collaboration.
Summary of project results
The increase of solar cell efficiency and the decrease of their production cost are the main objectives of research in the photovoltaic field. The PERPHECT project idea appeared, by the sudden and unexpected progress published in the fall of 2013 regarding solar cells that use halide compounds with perovskite structure as a photon absorber. Within the PERPHECT project all the research efforts were done to understand the charge carrier generation and transport processes in the halide perovskite photoactive material and in the whole cell structure in order to find solutions for: increase PCE and the stability over time of the solar cells; replacing the ITO or FTO transparent electrode with other transparent oxide materials that are more environmentally friendly, or with metallic webs that are applicable in flexible structures; replacing the electron transporting material TiO2 with another transparent oxide with perovskite structure and internal polarization (a ferroelectric material); development of a cheap technology for the fabrication of solar cells on large surfaces, based on printing techniques that will also permit the deposition of solar cells on flexible substrates and with transparent electrodes on both sides of the solar cell. The project holds significant fundamental research results (e.g. DOI:10.1016/j.solmat.2016.09.012, DOI:10.1021/acs.jpclett.6b02375, DOI:10.1039/C5CP05466D, DOI:10.1021/acs.jpcc.5b05823, DOI:10.1016/j.solmat.2015.10.023, DOI:10.1021/acs.jpcc.7b00399, DOI:10.1021/acs.jpcc.7b04248) regarding the internal working mechanisms and the proper measurement procedure of this type of cells, including the replacement of TiO2 with ferroelectric materials and the FTO with other transparent conductive oxides, resulting in the publishing of 11 articles in ISI journals with a cumulative impact factor of 48,5, a patent application and 4 doctoral thesis of which 3 in the stage of completion. The performance of solar cells with halide perovskite in the standard configuration with photovoltaic conversion efficiencies (PCE) of 15.4%, representing record values in Romania and donor states have been obtained on perovskite solar cells. The value of 15.4% represents a average value between the values determine for the Current-Voltage curves (J-V) measured with a slow scan speed (20 mV/s) form the open circuit voltage (Voc) to 0V, where the PCE is 16.2% and from 0V to the Voc in which case the PCE is 14.6%.
Summary of bilateral results
The three partners from the donor states (P1, P2 and P3) participated in the AZO and /or TiO2 layers fabrication, physico-chemical characterization (P1 and P2 together with PP and P5) and the elaboration of the developed theoretical models (P3 together with PP and P4). The Romanian partners conducted research on the deposition and characterization of halide perovskite layers (PP and P5 by spin-coating and printing, P4 by evaporation), PTO and BTO ferroelectric layers (PP), spiro-OMeTAD (PP and P5) and Mo /Ag (PP), metal nano-webs (PPs) as well as the production of the prototype printing equipment (P5 and PP). The partnership enabled the enlargement of expertise of the researchers involved in the project, exchange of scientific information between the partners contributing to the success of the project and the realization of scientific papers published in prestigious journals, thus offering opportunities for new collaborations between partners, including on other calls, such as MERANet, currently funded between PP and P3). Joint applications are also considered for future competitions launched under the EEA program). This partnership, although based on fundamental research, demonstrated that high degree of applicability through the fabrication of high efficiency perovskite based photovoltaic devices, able to be manufactured with inexpensive techniques that can, ultimately lead to a significant reduction in production costs over Si based solar cells. Through this partnership we developed perovskite solar cells (PSCs), stable over time, with efficient photovoltaic conversion averaging 15.4% on standard geometry (record values for Romania and donor states) and up to 10.2% on flexible PSCs, where FTO electrodes were replaced by metallic nano-webs (again a unique result at international level and not yet reported in the literature). Theoretical models for layers / interfaces have been developed in the PSCs as well as a thorough description of the dynamic electrical behaviour within this type of solar cells. The correlation between experiments and theory has resulted in a better understanding of the physical phenomena that determine PSCs performance, allowing the optimization of devices based on knowledge and not by trial&error procedures. Finally, the PSCs printing equipment was manufactured.