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This work reports the use of the chip-based GaN-based micro-LED (μLED) arrays for multifunctional applications as microdisplay, data transmitters, photodetectors, and solar cells. The functions of display and transmitter have been reported, and particularly, we experimentally demonstrated that μLED arrays could be used as self-powered, high-performance, and wavelength-selective photodetectors (PDs), enabling high-speed multiple-input multiple-output (MIMO) visible light communications (VLC) under on−off keying (OOK) modulation scheme using 405 nm violet laser diodes (LDs) as transmitters. The optoelectronic and communication characteristics of the μLED-based PDs with diameters of 40, 60 and 100 μm were systematically studied. The optoelectronic analysis shows superior performances of μLEDbased PDs at a 405 nm wavelength compared with other previously reported GaN-based PDs. Under a bias voltage of −5 V, the comparable peak responsivities of 0.27, 0.31, and 0.24 A/W, specific detectivities of 1.1 × 10 11 , 2.3 × 10 12 , and 2.1 × 10 12 cm H 1/2 W −1 , and linear dynamic ranges (LDRs) of 152, 162, and 164 dB were achieved for 40, 60, and 100 μm μLEDs, respectively. Even at zero-bias, that is, self-powered mode, we have achieved high peak responsivities of 0.24, 0.29, and 0.21 A/ W, high specific detectivities of 7.5 × 10 12 , 1.5 × 10 13 , and 1.3 × 10 13 cm H 1/2 W −1 , and high LDR up to 186, 196, and 197 dB for 40, 60, and 100 μm μLEDs, respectively. The μLEDs could also be used to harvest the optical energy of the system, working as solar cells. The μLED-based PD arrays were tested as receivers in the VLC system to implement high-speed parallel communication, which yields maximum data rates of 180, 175, and 185 Mbps for single 40, 60, and 100 μm μLED-based PDs at a distance of 1 m with BERs of 3.5 × 10 −3 , 3.7 × 10 −3 , and 3.5 × 10 −3 , respectively. Furthermore, the 2 × 2 MIMO parallel VLC system was achieved to increase the VLC data rate, which suggests the potential of using large μLED-based PD arrays for multiple Gbps and even Tbps VLC applications.

Infrared spectra of mass-selected homoleptic iron carbonyl cluster cations including mononuclear Fe(CO) 5+ and Fe(CO) 6 + , dinuclear Fe 2 (CO) 8 + and Fe 2 (CO) 9 + , and trinuclear Fe 3 (CO) 12 + are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. Only one IR band is observed for the Fe(CO) 5 + cation, which is predicted to have a C 4v structure. The Fe(CO) 6 + cation is determined to be a weakly bound complex involving a Fe(CO) 5 + core ion. In contrast to neutral clusters which have symmetric structures with two and three bridging carbonyl ligands, the dinuclear Fe 2 (CO) 8 + and Fe 2 (CO) 9 + cations are characterized to have unbridged asymmetric (OC) 5 Fe-Fe(CO) n + (n ¼ 3 and 4) structures. The trinuclear Fe 3 (CO) 12 + cluster cation is determined to have an open chain like (OC) 5Fe-Fe(CO) 2 -Fe(CO) 5 structure instead of the triangular structure with two bridging CO groups for the Fe 3 (CO) 12 neutral. The di-and trinuclear cluster cations all involve a square pyramid like Fe(CO) 5 building block that satisfies the 18-electron configuration of this iron center. The Fe(CO) 5 building block is isolobal to the CH 3 fragment in hydrocarbon chemistry, the Fe 2 (CO) 9 + and Fe 3 (CO) 12 + cluster cations may be considered through isolobality to be metal carbonyl analogues of the ethyl and isopropyl cations.