25 KB182 KB23 KB200020242003Bratina, GvidoHudej, RobertPavlica, Egonletnik:37številka:55 stranistr. 225-229ISSN:1580-2949COBISSID:283643URN:URN:NBN:SI:doc-0A5SFRD3enInštitut za kovinske materiale in tehnologijeMateriali in tehnologijekristalimehanizmimetoda Monte CarloMonte Carlo methodorganske spojinepolprevodnikiprevajanjetranslationTransport električnega naboja v organskih polprevodnikih, simulacija po metodi Monte Carlo| Electric-charge transport in organic semiconductors: a Monte Carlo simulation|The electric-charge transport in organic semiconductors is essentially different to the transport in ordered inorganic crystals. The reason is in thelocalization of the energy states, which act as charge-carrier transport channels between molecules. Consequently, the determination of the basic transport parameters in organic materials is inherently more involved than in their inorganic counterparts. The analytical methods that are used to describe charge transport in inorganic materials are unsuitable, since they are based on the extended electronic energy structure. We report here on the simulation of charge transport in organic semiconductor thin films. The simulation is based on the Monte Carlo method and describes the charge-carrier transport within the framework of carrier hopping between the sites. We employed a Gaussian energy distribution of the hopping sites with disorder elements. The degree of disorder is characterized by the width of the Gaussian distribution and is measured in eV units. The results of the transport simulation in 3,4,9,10-perylenedianhydride tetracarboxylic acid (PTCDA) show that the photogenerated charge-carrier current depends on the film thickness, temperature and disorder degree. The simulated photocurrents have the same amplitude in thick films as in the thin films, but the overall shape of the I(t) curve is more dispersive in thin films. The charge-carrier mobility decreases with the increasing degree of disorder at a given temperature. The simulation of the photogenerated positive charge carriers current matches with the time-of-flight experiment in a glass/ITO/PTCDA(600 nm)/In heterostructure at room temperature and an applied bias voltage of 8 VTransport nosilcev elektriřnega naboja v organskih polprevodnikih se bistveno razlikuje od transporta v urejenih anorganskih kristalih. Razlog za to je lokalizacija energijskih stanj, ki omogočajo prehode nosilcev naboja med molekulami. Posledično je določanje osnovnih parametrov organskih materialov, kot je npr. gibljivost naboja, bistveno težje, tako eksperimentalno kot teoretsko. Analitične metode, ki jih uporabljamo za opis gibljivosti nosilcev naboja v anorganskih materialih so v organskih neustrezne, saj upoštevajo razširjeno elektronsko energijsko strukturo. V pričujočem prispevku predstavljamo simulacije transporta nosilcev naboja v tankih plasteh organskih polprevodnikov. Simulacija temelji na metodi Monte Carlo in opisuje transport nosilcev naboja v okviru teorije poskakovanja med stanji, katerih energijska porazdelitev je Gaussova z elementi nereda. Stopnjonereda merimo s širino Gaussove porazdelitve v eV. Rezultati simulacije transporta v 3,4,9,1O-perilendianhidridu tetrakarboksilnekisline (PTCDA) kažejo na odvisnost oblike toka fotovzbujenih nosilcev naboja od debeline plasti, temperature in velikosti nereda. Simulirani fotovzbujeni tokovi v tanjših plasteh imajo enako amplitudo kot v debelejših, njihova oblika pa je bolj disperzivna. Gibljivost nosilcev naboja strmo pada z večanjem stopnje nereda pri dani temperaturi. Simulacija toka fotovzbujenih nosilcev naboja pozitivnega predznaka se ujema s poskusom časa preleta v strukturi steklo/ITO/PTCDA (600 nm)/In pri sobni temperaturi in zunanji napetosti 8 VTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije