Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control.
نویسندگان
چکیده
Infrared light-emitting diodes are currently fabricated from direct-gap semiconductors using epitaxy, which makes them expensive and difficult to integrate with other materials. Light-emitting diodes based on colloidal semiconductor quantum dots, on the other hand, can be solution-processed at low cost, and can be directly integrated with silicon. However, so far, exciton dissociation and recombination have not been well controlled in these devices, and this has limited their performance. Here, by tuning the distance between adjacent PbS quantum dots, we fabricate thin-film quantum-dot light-emitting diodes that operate at infrared wavelengths with radiances (6.4 W sr(-1) m(-2)) eight times higher and external quantum efficiencies (2.0%) two times higher than the highest values previously reported. The distance between adjacent dots is tuned over a range of 1.3 nm by varying the lengths of the linker molecules from three to eight CH(2) groups, which allows us to achieve the optimum balance between charge injection and radiative exciton recombination. The electroluminescent powers of the best devices are comparable to those produced by commercial InGaAsP light-emitting diodes. By varying the size of the quantum dots, we can tune the emission wavelengths between 800 and 1,850 nm.
منابع مشابه
Light-Emitting Quantum Dot Transistors: Emission at High Charge Carrier Densities
For the application of colloidal semiconductor quantum dots in optoelectronic devices, for example, solar cells and light-emitting diodes, it is crucial to understand and control their charge transport and recombination dynamics at high carrier densities. Both can be studied in ambipolar, light-emitting field-effect transistors (LEFETs). Here, we report the first quantum dot light-emitting tran...
متن کاملpH Effect on the Size of Graphene Quantum dot Synthesized by Using Pulse Laser Irradiation
In this study graphene oxide (GO) was synthesized by using Hummer’s method. Low dimension graphene quantum dot nanoparticles (GQDs) were synthesized using pulse laser irradiation. Fourier Transform-Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) spectroscopy and photoluminescence (PL) analysis were applied to study the GQDs characteristic. Scanning electron microscopy illustrated the...
متن کاملIII-V compound semiconductor nanostructures on silicon: Epitaxial growth, properties, and applications in light emitting diodes and lasers
Significant developments have occurred in the area of III-V compound semiconductor nanostructures. The scope of developments includes quantum dots and nanowires epitaxially grown on Si substrates, as well as their applications in light emitting diodes and lasers. Such nanoscale heterostructures exhibit remarkable structural, electrical, and optical properties. The highly effective lateral stres...
متن کاملEnhanced Performance of Quantum Dot-Based Light-Emitting Diodes with Gold Nanoparticle-Doped Hole Injection Layer
UNLABELLED In this paper, the performance of quantum dot-based light-emitting diodes (QLEDs) comprising ZnCdSe/ZnS core-shell QDs as an emitting layer were enhanced by employing Au-doped poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate ( PEDOT PSS) hole injection layer (HIL). By varying the concentration and dimension of Au nanoparticle (NP) dopants in PEDOT PSS, the optimal devices w...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Nature nanotechnology
دوره 7 6 شماره
صفحات -
تاریخ انتشار 2012