Using the finite-time thermodynamics, an irreversible cycle model of the Stirling refrigeration-cycle, using a ferroelectric material as the working substance, is established. Several irreversibilities due to thermal resistances between the working substance and the heat reservoirs, regenerative losses in two regenerative processes are taken into account. The influence of these irreversible losses on the performance of the ferroelectric Stirling refrigeration-cycleis analyzed. The thermoeconomic optimization for ferroelectric Stirling refrigeration-cycle is reported. The cooling load for the refrigerator per unit total cost is proposed as objective functions for the optimization. The optimum performance parameters which maximize the objective functions are investigated. Since the optimization technique consists of both investment and energy consumption costs, the obtained results are more general and realistic.

A orange organic light-emitting device has been fabricated with a structure of ITO/m-MTDATA (45 nm)/NPB (8 nm)/ DPVBi:DCJTB 0.5 % (15 nm)/TPBi (x nm)/Alq3[(60-x) n /LiF (1 nm)/Al£¬where x=0, 4, 7 and 10, respectively. N-arylbenzinmidzoles (TPBi) was used as the excton-blocking layer resulting mixture of lights from DPVBi molecules (blue-light) and DCJTB (yellow-light) molecules, thereby producing orange light emission. The performance of device can be readily adjusted by only varying the thickness of the TPBi layer. The Commission Internationale de 1'Eclairage (CIE) coordinates of the device are largely insensitive to diffrent of the driving voltages. When the thickness of TPBi is 7 nm, the device exhibits peak efficiency of 6.16 cd/A at the applied voltage of 8 V, and the maximum brightness is 43310 cd/m2at 15 V, respectively.

A white organic light emitting device (WOLED) with excton confining structure is reported. The blue and red emitting layer consist of 1,4bis (2,2-diphenyl vinyl) benzene (DPVBi) and the bis (1-(phenyl) isoquinoline) iridium (III) acetylanetonate [Ir (piq)2(acac)] doped into 4,4(-N,N)-dicarbazole-biphenyl (CBP) host, respectively. The devices were made of ITO/ m-MTDATA (40 nm)/ NPB (10 nm) /DPVBi (8 nm)/ Bhen (xnm)/ CBP: Ir (piq)2(acac) 2% 5nm/ Alq (50 nm )/ LiF (1 nm)/Al (200 nm), by adding excton confining layer, with only a small increase in operating voltage. However, the efficiency of device increases. The electroluminescent (EL) spectra exhibit two peaks at 456 and 628 nm, resulting in white light emission with the Commission Internationale dEclairage (CIE) chromaticity coordinates of (0.222, 0.2402) at 4V to (0.1924, 0.1986) at 13V whenxis 8, while the device shows the current efficiency of 4.79 cd/A at 6V, its maximum luminance is 14130 cd/m2at 13V, respectively.

An organic emitting device with well structure is reported. The well structure fabricated by alternating deposition of constituent tris-(8-hydroxyquinoline) aluminum (Alq) and 4, 7-diphenyl-1, 10-phenanthroline (BPhen) layers improved the current efficiency. The enhanced efficiency can be attributed to the strong accumulation of electrons and holes in the emitting layer, which leads to an increase of the exciton formation and exciton recombination probability. The single well device exhibits the highest current efficiency of 4.12cd/A at 4V, which is more than 1.2 times than that of the conventional organic light-emitting devices. It is an effective and simple way to improve the efficiency of the organic devices by utilizing well structure as the emitting layer with proper well number.

An organic light emitting device (OLED) with multilayer structure is reported. The devices were made of ITO/ m-MTDATA (45 nm)/ NPB (10 nm) / DCJTB (0.05 nm)/DPVBi (x nm)/ Alq:QAD 0.5% 20nm /Alq (50-x nm)/LiF(1nm)/Al, by doping combine with non-doping method. The ultrathin layer was introduced for the yellow emitting layer by using 4- (dicyanomethylene)-2-tert-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). The ultrathin layer offered an attraction in that it allowed the easy handling process and accurate thickness control, it enabled high device efficiency with simple architecture.The device shows the current efficiency of 2.79 cd/A at 12V, its maximum luminance is 17450 cd/m2 at 14V, respectively.