Ciftpinar, Emine Hande
The design and development of high-efficiency interdigitated back contact (IBC) solar cells have been studied within the scope of this thesis. Developing a totally industry-compatible, lithography-free, high-throughput process flow for IBC cell fabrication was the main motivation of the thesis. For this, a detailed simulation study was conducted using Quokka 2 software to optimize the rear side cell geometry and understand the effect of bulk and layer properties on the device performance. After determining three different cell geometries with varying pitch values of 750, 1250, and 1700 µm, a totally screen-printing-based process flow was designed and applied to fabricate IBC cells. For selective diffusion, thick SiNx layers with optimized layer compositions were used as the diffusion barriers during the high-temperature boron and phosphorus diffusion process. The patterning of the barrier layers was done using a screen-printable ink with enhanced chemical resistance in acidic solutions. Following the optimization of the diffusion barrier properties and corresponding patterning step, diffusion and corresponding passivation properties were optimized. BCl3 and POCl3 diffusion recipes were studied in detail not only for the rear emitter and back surface field (BSF) regions but also for the front non-contacted junctions. Industrial fire-through (FT) metals pastes were used for the metallization of rear junctions whose corresponding optimization was done with the help of detailed contact resistivity analysis. Combining all optimized process parameters for the cell fabrication resulted in best cell parameters as FF:71.2%, Voc:642 mV, Jsc:37 mA/cm2 for FFE-IBC cell structure which were FF:70.3%, Voc:637 mV, Jsc:39 mA/cm2 for FSF-IBC structure. In addition to IBC studies, polySi passivating contact cells were also focused on in this thesis. In addition to their passivating properties, ex-situ doped polySi layers of varying thicknesses were studied also for their contacting properties. Excellent passivation properties were obtained for the case of n-polySi layers with the corresponding total recombination parameters (J0) of 1.6 and 7.4 fA/cm2 on textured and polished wafers, respectively. For the case of p-polySi layers, 16.3 and 70.2 fA/cm2 were obtained on the polished and textured wafers. Regarding the contacting properties, a novel methodology to extract the contact recombination parameter (J0,contact) was developed. The extracted J0,contact values were lying within the range of 300-400 fA/cm2 for relatively thicker n-polySi and p-polySi layers which increased to 1000 and 700 fA/cm2 for their thinner counterparts. Obtained J0,contact values were then correlated to high-resolution SEM images to better understand the contact formation and paste-polySi interaction.


Simulation of an efficient silicon heterostructure solar cell concept featuring molybdenum oxide carrier-selective contact
MEHMOOD, Haris; NASSER, Hisham; Tauqeer, Tauseef; HUSSAIN, Shahzad; Ozkol, Engin; Turan, Raşit (2018-03-25)
Transition metal oxides/silicon heterocontact solar cells are the subject of intense research efforts owing to their simpler processing steps and reduced parasitic absorption as compared with the traditional silicon heterostructure counterparts. Recently, molybdenum oxide (MoOx, x<3) has emerged as an integral transition metal oxide for crystalline silicon (cSi)-based solar cell based on carrier-selective contacts (CSCs). In this paper, we physically modelled the CSC-based cSi solar cell featuring MoOx/intr...
Dual-band high-frequency metamaterial absorber based on patch resonator for solar cell applications and its enhancement with graphene layers
Ustunsoy, Mehmet Pasa; Sabah, Cumali (2016-12-05)
In this paper, a dual-band high-frequency metamaterial absorber based on patch resonator is designed and analyzed for solar cells. In order to obtain a metamaterial absorber, metal-semiconductor-metal layers are combined. The results of the designed structure are shown in the infrared and visible ranges of solar spectrum. Structural parameters and dimensions of the device have a significant importance on the performance of the designed absorber. The simulations are carried out with full-wave electromagnetic...
Yaşa, Mustafa; Toppare, Levent Kamil; Arslan Udum, Yasemin; Department of Polymer Science and Technology (2022-1-27)
There are several studies on organic solar cells based on conjugated polymers in literature, and various new materials are being designed. The Donor-Acceptor approach has been the most common approach for designing and synthesizing conjugated polymers. In this study, thienopyrroledione bearing conjugated polymers were synthesized via Stille and Suzuki polycondensation reactions. In the first part of this thesis, the polymers obtained via Stille polycondensation were employed to fabricate organic solar cells...
Germanium solar cells prepared by ion implantation
Kabacelik, Ismail; Turan, Raşit (2013-09-01)
Development of Ge solar cells for multijunction solar cells, where the p-n junction is formed by ion implantation is investigated. Ge samples are doped by phosphorus (P) ions having 60 keV energy at dose ratios of 1x10(13), 1x10(14), 1x10(16) ve 1x10(16) ions/cm(2) at room temperature. The influences of P concentration and activation temperature on Ge solar cells is investigated. P concentration and layer resistance are measured by secondary ion mass spectrometry (SIMS) and a 4-point probe, respectively. La...
Polymer light emitting diodes and organic solar cells towards ito free devices and high efficiency devices using electrochemically synthesized polymers /
Hızalan Özsoy, Gönül; Toppare, Levent Kamil; Department of Chemistry (2017)
In this study, polymer based solar cells and polymer based light emitting diodes were constructed. In the third and fourth chapters of this study, effect of terminal units and effect of molecular weight on electroluminescence and photovoltaic properties were investigated. Triphenyl end capped polymer P1 based PLED shows luminance value of 10411cd/m2 at 8.5V whereas benzene end capped polymer P2 based PLED has the peak luminance value of 14583cd/m2 at 8V. P2 based photovoltaic devices exhibited superior perf...
Citation Formats
E. H. Ciftpinar, “DESIGN, FABRICATION AND CHARACTERIZATION OF INTERDIGITATED BACK CONTACT SOLAR CELLS,” Ph.D. - Doctoral Program, Middle East Technical University, 2022.