Study On The Properties Of ATO Transparent Conductive Films And Its Application In Organic Solar Cells

In recent years, organic solar cells （OSCs） have been considered the most cost-effectivenext-generation solar cells due to its simple preparation, low cost, flexibility and mass production. OSCshave attracted worldwide attention in the world also. In order to achieve the commercialization of OSCs assoon as possible, to further reduce the preparation cost and improve the photoelectric conversion efficiencyis the most important task and the current international hot research field also. Nowadays, in most OSCs,indium tin oxide （ITO） transparent conductive oxide film is used as transparency electrode. However，theprice of ITO is high and its chemical stability in acid environment is poor. Therefore, many people havebeen studying in order to research the more excellent performance transparent electroconductive thin filmto replace the ITO film which is used as the electrode in the OSCs. The transparent electroconductive thinfilm of Sb-doped SnO₂（ATO） have many advantages, compared to the ITO films, low price, good chemicalstability and thermal stability. The above characteristics indicated that the ATO films have better applicationprospect in the OSCs. Therefore, the research on ATO transparent conductive films is very meaningful. Thecharacteristics of ATO film and its application in OSCs are studied in this article.1. The ATO films with different thicknesses and different argon-oxygen ratio are deposited by RFmagnetron sputtering on glass substrates. The properties of ATO thin films are characterized by using X-raydiffraction, Hall, four-point probe, X-ray photoelectron spectroscopy, transmission spectroscopy. Theresearch results show that the valence of Sb ion changes from Sb3+to Sb5+with the increase of O₂/Ar ratioand conductive properties of the films become better. The optimal parameters: the substrate temperature of600°C, the oxygen partial pressure of0.5Pa, the argon gas partial pressure of20Pa, a sputtering time of15min. The resistivity of film obtained under this condition is the lowest （1.99×10-3·cm）, thecorresponding carrier concentration and Hall mobility is3.0×1020cm-3and21.61cm2V-1s-1,respectively. The average transmittance of all the films is greater than85%in the visible light region whichmeans that ATO films are applicable to used as the transparent electrode of the OSCs. Then the OSC isprepared on the best conductive ATO film, the performance testing of devices shows that the open circuitvoltage （Voc） is0.4V, the short-circuit current density （Jsc） is3mA/cm2, the fill factor （FF） is22%, the photoelectric conversion efficiency is1.12%.2. The ATO films with the thickness of5to15nm are deposited on ITO coated glass substrate by RFmagnetron sputtering. The properties of ATO/ITO bilayer films are characterized by using X-ray diffraction,transmission spectra and field emission scanning electron microscopy. The results proved that the chemicalstability of ATO/ITO bilayer films is superior to the ITO film, but its optical properties and the conductivesubstantially constant. The OSCs with the structure of ITO/ATO/PEDOT:PSS/P3HT: PCBM/Al is preparedon the ATO/ITO bilayer films, the device without ATO film is prepared also for comparison. The resultsshow that the ATO film can improve the photoelectric conversion performance of the organic solar cell. Thedevice has the best photoelectric conversion efficiency of2.43%when the thickness of ATO is10nmwhich has a13%increase with respect to the device without ATO film. In addition, the reason why thephotoelectric conversion efficiency increases is discussed.