High Ambipolar and Balanced Carrier Mobility in Regioregular Poly(3-hexylthiophene)

The carrier transport of carefully purified regioregular poly(3-hexylthiophene) films was studied using time-of-flight photocurrent measurements. The authors find balanced ambipolar transport with a room-temp. mobility for holes of 3 * 10-4 cm2 V-1 s-1 and for electrons of 1.5 * 10-4 cm2 V-1 s-1 at elec. fields &gt;=105 V/cm. The transport is relatively field independent and weakly temp. dependent, pointing to a high degree of chem. regioregularity and purity. These factors make poly(3-hexylthiophene) attractive for use in a range of electronic applications.</p

High Ambipolar and Balanced Carrier Mobility in Regioregular Poly(3-hexylthiophene)

The carrier transport of carefully purified regioregular poly(3-hexylthiophene) films was studied using time-of-flight photocurrent measurements. The authors find balanced ambipolar transport with a room-temp. mobility for holes of 3 * 10-4 cm2 V-1 s-1 and for electrons of 1.5 * 10-4 cm2 V-1 s-1 at elec. fields >=105 V/cm. The transport is relatively field independent and weakly temp. dependent, pointing to a high degree of chem. regioregularity and purity. These factors make poly(3-hexylthiophene) attractive for use in a range of electronic applications.</p

Theoretical and experimental analysis of 1.3-mu m InGaAsN/GaAs lasers

We present a comprehensive theoretical and experimental analysis of 1.3-mum InGaAsN/GaAs lasers. After introducing the 10-band k . p Hamiltonian which predicts transition energies observed experimentally, we employ it to investigate laser properties of ideal and real InGaAsN/GaAs laser devices. Our calculations show that the addition of N reduces the peak gain and differential gain at fixed carrier density, although the gain saturation value and the peak gain as a function of radiative current density are largely unchanged due to the incorporation of N. The gain characteristics are optimized by including the minimum amount of nitrogen necessary to prevent strain relaxation at the given well thickness. The measured spontaneous emission and gain characteristics of real devices are well described by the theoretical model. Our analysis shows that the threshold current is dominated by nonradiative, defect-related recombination. Elimination of these losses would enable laser characteristics comparable with the best InGaAsP/InP-based lasers with the added advantages provided by the GaAs system that are important for vertical integration.</p

Experimental and theoretical analysis of the recombination processes in GaInNAs 1.3 μm Lasers

The recombination processes in GaInNAs 1.3 μm lasers were analyzed theoretically and experimentally. The threshold current was determined by measuring the light emitted from the lasers. The variation of threshold current with temperature and pressure the for quantum well devices was also studied

Experimental and theoretical analysis of the recombination processes in GaInNAs 1.3 μm Lasers

The recombination processes in GaInNAs 1.3 μm lasers were analyzed theoretically and experimentally. The threshold current was determined by measuring the light emitted from the lasers. The variation of threshold current with temperature and pressure the for quantum well devices was also studied

Theoretical and experimental analysis of 1.3 ?m InGaAsN/GaAs lasers

We present a comprehensive theoretical and experimental analysis of 1.3-mum InGaAsN/GaAs lasers. After introducing the 10-band k . p Hamiltonian which predicts transition energies observed experimentally, we employ it to investigate laser properties of ideal and real InGaAsN/GaAs laser devices. Our calculations show that the addition of N reduces the peak gain and differential gain at fixed carrier density, although the gain saturation value and the peak gain as a function of radiative current density are largely unchanged due to the incorporation of N. The gain characteristics are optimized by including the minimum amount of nitrogen necessary to prevent strain relaxation at the given well thickness. The measured spontaneous emission and gain characteristics of real devices are well described by the theoretical model. Our analysis shows that the threshold current is dominated by nonradiative, defect-related recombination. Elimination of these losses would enable laser characteristics comparable with the best InGaAsP/InP-based lasers with the added advantages provided by the GaAs system that are important for vertical integration.</p

Influence of the hole transporting layer on the thermal stability of inverted organic photovoltaics using accelerated-heat lifetime protocols

High power conversion efficiency (PCE) inverted organic photovoltaics (OPVs) usually use thermally evaporated MoO3 as a hole transporting layer (HTL). Despite the high PCE values reported, stability investigations are still limited and the exact degradation mechanisms of inverted OPVs using thermally evaporated MoO3 HTL remain unclear under different environmental stress factors. In this study, we monitor the accelerated lifetime performance under the ISOS-D-2 protocol (heat conditions 65 °C) of nonencapsulated inverted OPVs based on the thiophene-based active layer materials poly(3-hexylthiophene) (P3HT), poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7), and thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTTT) blended with [6,6]-phenyl C71-butyric acid methyl ester (PC[70]BM). The presented investigation of degradation mechanisms focus on optimized P3HT:PC[70]BM-based inverted OPVs. Specifically, we present a systematic study on the thermal stability of inverted P3HT:PC[70]BM OPVs using solution-processed poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and evaporated MoO3 HTL. Using a series of measurements and reverse engineering methods, we report that the P3HT:PC[70]BM/MoO3 interface is the main origin of failure of the P3HT:PC[70]BM-based inverted OPVs under intense heat conditions, a trend that is also observed for the other two thiophene-based polymers used in this study