Showing papers on "Organic solar cell published in 1990"

Effect of Thin Gold Interstitial-layer on the Photovoltaic Properties of Tandem Organic Solar Cell

Abstract: Tandem type organic solar cell consisting of two combined unit cells was fabricated. Each unit cell was two-layer organic solar cell composed of metal-free phthalocyanine and perylene tetracarboxylic derivative. When ultra-thin Au layer was inserted between unit cells, photovoltage increased about 2 times, while photocurrent density was much dependent on the thickness of the inserted Au layer.

Doping Effect on the Two-layer Organic Solar Cell

Abstract: Doping effect on an organic solar cell composed of two-layer thin pigment films of metal-free phthalocyanine (H2Pc) and perylene tetracarboxylic derivative (Me-PTC) was investigated. When H2 or NH3 was doped to the Me-PTC film during vacuum deposition, the photocurrent density drastically increased and the power conversion efficiency of the cell reached about 1% even under 75 mW cm−2 white light.

Doping effect on organic solar cell using quinacridone pigment.

Abstract: キナクリドン顔料薄膜とCdS薄膜を積層したp-nヘテロ接合型有機太陽電池において, キナクリドン顔料の精製, 電子受容性分子であるヨウ素 (I2) のドーピングによってセルの光起電力特性を向上させることができ, 内部光電変換効率0.15%が得られた. I2ドープを行う顔料膜厚を種々変化させ, CdS/キナクリドン接合の特性がドーピングによってどのような影響を受けているか探った. その結果, ドープされたI2はアクセプターとして働き, 顔料側の空乏層の電位勾配を増大させていること, CdSと顔料との間に分配される空乏層幅の割合を変化させていることが明らかとなった.

Electrical parameter changes in silicon solar cells induced by thermal donor formation

Abstract: Statistical results of 450 degrees C annealing experiments of variable duration, performed on n/sup +/pp+, 10 Omega -cm Czochralski silicon (Cz silicon), bifacial solar cells are presented. The specific temperature used is known to favor the nucleation of interstitial oxygen, creating the thermal donors, with important effects on the electrical properties of Cz silicon. Two distinct behaviors are observed with solar cells. The annealing during moderate time (below 4-5 h) leads, on average, to an improvement of the photovoltaic performances. Longer heat treatments (mainly above 8 h) induce an effective inversion of the base polarity (from p type to n type), with the net result of partially losing the precedent benefits. Both phenomena have been found to be permanent, provided further processes at higher temperatures are avoided. >

Algaas Top Solar Cell for Mechanical Attachment in a Multi-Junction Tandem Concentrator Solar Cell Stack

Abstract: Free-standing, transparent, tunable bandgap Al/sub x/Ga/sub 1-x/As top solar cells have been fabricated for mechanical attachment in a four terminal tandem stack solar cell. Evaluation of the device results have demonstrated 1.80 eV top solar cells with efficiencies of 18% (100X, AM0) which would yield stack efficiencies of 31% (100X, AM0) with a silicon bottom cell. When fully developed the Al/sub x/Ga/sub 1-x/As/Si mechanically-stacked two-junction solar cell concentrator system can provide efficiencies of 36% (AM0, 100X). AstroPower has fabricated Al/sub x/Ga/sub 1-x/As top solar cells with bandgaps from 1.66 eV to 2.08 eV. Liquid phase epitaxy (LPE) growth techniques have been used and LPE has been found to yield superior Al/sub x/Ga/sub 1-x/As material when compared to MBE or MOCVD. The result of this work is the first demonstration of a free-standing wide bandgap top cell technology which can be readily developed for commercial availability based on the Al-Ga-As mixed crystal system. Free-standing, tunable bandgap top solar cells with over 95% transparency to sub-bandgap photons will be made commercially available. The stack assembly technology will be readily applicable to any mechanically stacked multi-junction (MSMJ) system. Development of a wide bandgap top Solar cell is the only feasible method to obtain stack efficiencies greater than 40% at AM0. System efficiencies of greater than 40% can be realized when the AlGaAs top Solar cell is used in a three solar cell mechanical stack. This is a unique approach to improve the performance of space photovoltaic power systems.

Sub-band gap photocurrent in reverse biased p-i-n a-Si:H solar cells

Abstract: The spectra of the primary photocurrent excited by subband-gap radiation in p-i-n solar cells were simulated by solving the full set of transport equations. The expressions of the distribution function and of the recombination rate were modified to take into account the effects of subband-gap generation. The relationship between these spectra and the absorption coefficient was analyzed for different sets of the parameters involved in the simulation. It was concluded that the absorption coefficient as derived from the primary photocurrent is a good estimate of the absorption coefficient in the i-layer. In order to verify these concepts, measurements of the primary photocurrent on different kinds of p-i-n solar cells were performed. >