RESUMO
Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT: PSS) films as transparent electrodes for organic light-emitting diodes (OLEDs) are doped with a new solvent 1,3-dimethyl-2-imidazolidinone (DMI) and are optimized using solvent post-treatment. The DMI doped PEDOT: PSS films show significantly enhanced conductivities up to 812.1 S cm(-1) . The sheet resistance of the PEDOT: PSS films doped with DMI is further reduced by various solvent post-treatment. The effect of solvent post-treatment on DMI doped PEDOT: PSS films is investigated and is shown to reduce insulating PSS in the conductive films. The solvent posttreated PEDOT: PSS films are successfully employed as transparent electrodes in white OLEDs. It is shown that the efficiency of OLEDs with the optimized DMI doped PEDOT: PSS films is higher than that of reference OLEDs doped with a conventional solvent (ethylene glycol). The results present that the optimized PEDOT: PSS films with the new solvent of DMI can be a promising transparent electrode for low-cost, efficient ITO-free white OLEDs.
Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/química , Imidazóis/química , Luz , Polímeros/química , Poliestirenos/química , Condutividade Elétrica , Eletrodos , Estrutura Molecular , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
We have fabricated boron ion-implanted ZnO thin films by ion implantation into sputtered ZnO thin films on a glass substrate. An investigation of the effects of ion doses and activation time on the electrical and optical properties of the films has been made. The electrical sheet resistance and resistivity of the implanted films are observed to increase with increasing rapid thermal annealing (RTA) time, while decreasing as the ion dose increases. Without any RTA process, the variation of the carrier density is insensitive to the ion dose. With the RTA process, however, the carrier density of the implanted films increases and approaches that of the un-implanted ZnO film as the ion dose increases. On the other hand, the carrier mobility is shown to decrease with increasing ion doses when no RTA process is applied. With the RTA process, however, there is almost no change in the mobility. We have achieved the optical transmittance as high as 87% within the visible wavelength range up to 800 nm. It is also demonstrated that the work function can be engineered by changing the ion dose during the ion implantation process. We have found that the work function decreases as the ion dose increases.
Assuntos
Boro , Cristalização/métodos , Íons Pesados , Membranas Artificiais , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Óxido de Zinco/química , Condutividade Elétrica , Transferência de Energia/efeitos da radiação , Teste de Materiais , Nanotecnologia/métodos , Tamanho da Partícula , Doses de Radiação , Propriedades de Superfície/efeitos da radiação , Óxido de Zinco/efeitos da radiaçãoRESUMO
The work function of an Al-doped ZnO (AZO) thin film can be increased via B+ ion implantation from 3.92 eV up to 4.22 eV. The ion implantation has been carried out with the ion dose of 1 x 10(16) cm(-2) and ion energy of 5 keV. The resistance of the B+ implanted AZO films has been a bit raised, while their transmittance is slightly lowered, compared to those of un-implanted AZO films. These behaviors can be explained by the doping profile and the resultant band diagram. It is concluded that the coupling between the B+ ions and oxygen vacancies would be the main reason for an increase in the work function and a change in the other properties. We also address that the work function is more effectively alterable if the defect density of the top transparent conducting oxide layer can be controlled.