{
  "meta": {
    "api_type": "NWO Projects API",
    "version": "1.0.2",
    "licence": {
      "name": "CC0 1.0 Universal",
      "url": "https://creativecommons.org/publicdomain/zero/1.0",
      "description": "To the extent possible under law, all copyright and related or neighbouring rights have been waived worldwide to the data made available through this API."
    },
    "documentation": "https://doi.org/10.5281/zenodo.14918287",
    "release_date": "2025-08-20T00:00:00",
    "funder": "https://doi.org/10.13039/501100003246",
    "ror_id": "https://ror.org/04jsz6e67",
    "date": "2026-11-05T00:00:00",
    "count": 1,
    "per_page": 100,
    "pages": 1,
    "page": 1
  },
  "projects": [
    {
      "project_id": "700.53.308",
      "title": "Opto-electrical properties of quantum-dot molecules and solids",
      "funding_scheme_id": 2591,
      "funding_scheme": "TOP-subsidies 2004 CW",
      "department": "Exacte en Natuurwetenschappen",
      "sub_department": "Chemische Wetenschappen",
      "start_date": "2005-12-01T00:00:00",
      "end_date": "2011-06-29T00:00:00",
      "reporting_year": 2004,
      "summary_nl": "Reducing the size of semiconductor structures below the intrinsic wavelength of electronic charge carriers gives rise to pronounced changes in the energy level structure. With colloidal nanocrystals in the 1-10 nm range, the HOMO-LUMO optical gap can be tuned from the near IR through the visible to the near UV by variation of the size and shape of the nanocrystals. In addition, the conduction electron and valence hole energy levels are well separated in energy and possess atom-like (S, P, D&) symmetries. Semiconducting nanocrystals are therefore also referred to as quantum dots (QD?s) or artificial atoms. The energy separation between the atom-like states is in 100 meV range, which allows one to explore the quantum properties of such nanocrystals up to room temperature. World-wide, there is an extensive research effort on the synthesis of colloidal quantum dots and the optical and electrical properties of such systems. Since we started research in this area about seven years ago, our group has made important contributions to this field.  The combination of expertise in the preparation of high quality QD?s combined with a strong background in optical (laser) and electrical (conduction) spectroscopies provides a unique setting for research in this area. \n      The aim of the present proposal is to extend the research to artificial molecules and solids. QD molecules (dimers, trimers, &)  consist of a few nanocrystals bound by an organic backbone molecule that defines the symmetry and the degree of electronic coupling between the quantum dots. Quantum dot solids are (ordered) 2-D or 3-D arrays of nanocrystal building blocks assembled by covalent or hydrogen bonding or van der Waals interactions. Novel and intriguing optical and electrical properties will arise from electronic interactions between QD building blocks. The degree of electronic coupling between the atom-like orbitals can be varied by the nature of the building blocks, the distance between them and the nature of the organic bridges. We will explore the properties of quantum dot molecules and  solids from the weak to the strong coupling limit. Photo-induced electron transfers between atom-like energy levels and Coulomb interactions are expected to be important in the case of weak coupling. In the strong coupling limit, molecular-type wave functions and strong Coulomb and spin interactions will decide the optical and electrical properties of the quantum dot molecules and solids. Exciton energy transfer is an important phenomenon in optically excited molecules or solids. \n     Targeted synthesis of  quantum dot molecules starting from nanocrystal building blocks is far from trivial. For instance, addition of a properly functionalized organic linker x-x to a suspension of quantum dots A will lead to large agglomerates and not to the desired dimers Ax-xA. We will develop efficient preparation methods for homogeneous and heterogenous dimers (Ax-xA, Ax-yB) and trimers by combining the virtues of advanced organic chemistry and mass-selective separation methods (centrifuge, chromatography). The building blocks are colloidal II-VI an IV-VI semiconductor nanocrystals of controlled size and shape and with a high photoluminescence quantum yield. QD solids can be prepared from nanocrystal solutions by a number of established methods. We will also develop preparation methods for homogeneous and heterogeneous QD solids based on layer-by-layer deposition of ordered self-assembled monolayers. Such monolayers with variable composition and  inter-particle distance can be prepared in a Langmuir trough and transferred to a substrate.  \n      In analogy with previous work on single quantum dots, we will use resonant tunneling spectroscopy to study the energy level structure of quantum dot molecules and 2-D arrays. We will investigate the energy and shape of extended molecular-type orbitals, their electronic occupation, and spin and charge interactions. For these studies, we will use a vacuum STM-AFM operating between 20 and 1500 K that has been acquired recently by the Debye Institute. With optical spectroscopy we will study molecular-type electronic transitions which arise from the electronic coupling between the quantum dots. We will also study the exciton spin dynamics in a quantum dot molecule and compare this with the results obtained with quantum dots. In a QD molecule A-B selective excitation in A may be followed by electron transfer to B resulting in a long-lived charge-separated state A+-B-. Such indirect excitons have a strong scientific interest and are important for applications in photocatalysis, photon up-conversion and opto-electronic devices. The dynamics of electron-hole separation and back recombination will be studied by transient absorption and luminescence spectroscopy. In addition, the long-lived charge-separated state A+-B- forms the basis for the study of intra-band transitions and possibly, photon up-conversion with a quantum dot molecule. \n\tAt present research on QD molecules and solids is largely unexplored. With our strong background in the optical and electrical spectroscopy of QD?s we are in a good position to make a major contribution in this competitive and important field of research.  \n",
      "summary_en": "Reducing the size of semiconductor structures below the intrinsic wavelength of electronic charge carriers gives rise to pronounced changes in the energy level structure. With colloidal nanocrystals in the 1-10 nm range, the HOMO-LUMO optical gap can be tuned from the near IR through the visible to the near UV by variation of the size and shape of the nanocrystals. In addition, the conduction electron and valence hole energy levels are well separated in energy and possess atom-like (S, P, D&) symmetries. Semiconducting nanocrystals are therefore also referred to as quantum dots (QD?s) or artificial atoms. The energy separation between the atom-like states is in 100 meV range, which allows one to explore the quantum properties of such nanocrystals up to room temperature. World-wide, there is an extensive research effort on the synthesis of colloidal quantum dots and the optical and electrical properties of such systems. Since we started research in this area about seven years ago, our group has made important contributions to this field.  The combination of expertise in the preparation of high quality QD?s combined with a strong background in optical (laser) and electrical (conduction) spectroscopies provides a unique setting for research in this area. \n      The aim of the present proposal is to extend the research to artificial molecules and solids. QD molecules (dimers, trimers, &)  consist of a few nanocrystals bound by an organic backbone molecule that defines the symmetry and the degree of electronic coupling between the quantum dots. Quantum dot solids are (ordered) 2-D or 3-D arrays of nanocrystal building blocks assembled by covalent or hydrogen bonding or van der Waals interactions. Novel and intriguing optical and electrical properties will arise from electronic interactions between QD building blocks. The degree of electronic coupling between the atom-like orbitals can be varied by the nature of the building blocks, the distance between them and the nature of the organic bridges. We will explore the properties of quantum dot molecules and  solids from the weak to the strong coupling limit. Photo-induced electron transfers between atom-like energy levels and Coulomb interactions are expected to be important in the case of weak coupling. In the strong coupling limit, molecular-type wave functions and strong Coulomb and spin interactions will decide the optical and electrical properties of the quantum dot molecules and solids. Exciton energy transfer is an important phenomenon in optically excited molecules or solids. \n     Targeted synthesis of  quantum dot molecules starting from nanocrystal building blocks is far from trivial. For instance, addition of a properly functionalized organic linker x-x to a suspension of quantum dots A will lead to large agglomerates and not to the desired dimers Ax-xA. We will develop efficient preparation methods for homogeneous and heterogenous dimers (Ax-xA, Ax-yB) and trimers by combining the virtues of advanced organic chemistry and mass-selective separation methods (centrifuge, chromatography). The building blocks are colloidal II-VI an IV-VI semiconductor nanocrystals of controlled size and shape and with a high photoluminescence quantum yield. QD solids can be prepared from nanocrystal solutions by a number of established methods. We will also develop preparation methods for homogeneous and heterogeneous QD solids based on layer-by-layer deposition of ordered self-assembled monolayers. Such monolayers with variable composition and  inter-particle distance can be prepared in a Langmuir trough and transferred to a substrate.  \n      In analogy with previous work on single quantum dots, we will use resonant tunneling spectroscopy to study the energy level structure of quantum dot molecules and 2-D arrays. We will investigate the energy and shape of extended molecular-type orbitals, their electronic occupation, and spin and charge interactions. For these studies, we will use a vacuum STM-AFM operating between 20 and 1500 K that has been acquired recently by the Debye Institute. With optical spectroscopy we will study molecular-type electronic transitions which arise from the electronic coupling between the quantum dots. We will also study the exciton spin dynamics in a quantum dot molecule and compare this with the results obtained with quantum dots. In a QD molecule A-B selective excitation in A may be followed by electron transfer to B resulting in a long-lived charge-separated state A+-B-. Such indirect excitons have a strong scientific interest and are important for applications in photocatalysis, photon up-conversion and opto-electronic devices. The dynamics of electron-hole separation and back recombination will be studied by transient absorption and luminescence spectroscopy. In addition, the long-lived charge-separated state A+-B- forms the basis for the study of intra-band transitions and possibly, photon up-conversion with a quantum dot molecule. \n\tAt present research on QD molecules and solids is largely unexplored. With our strong background in the optical and electrical spectroscopy of QD?s we are in a good position to make a major contribution in this competitive and important field of research.  \n",
      "project_members": [
        {
          "role": "Researcher",
          "member_id": 206717,
          "last_name": "Li",
          "degree_post_nominal": "MSc",
          "initials": "H.Y.",
          "first_name": "Heng-Yu",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Condensed Matter and Interfaces",
          "organisation_id": 80942,
          "ror": "https://ror.org/04pp8hn57",
          "active": false
        },
        {
          "role": "Researcher",
          "member_id": 188077,
          "last_name": "Dorp",
          "degree_pre_nominal": "dr.",
          "initials": "D.H.",
          "first_name": "Dennis",
          "prefix": "van",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Condensed Matter and Interfaces",
          "organisation_id": 80942,
          "ror": "https://ror.org/04pp8hn57",
          "active": false
        },
        {
          "role": "Project leader",
          "member_id": 177557,
          "last_name": "Meijerink",
          "degree_pre_nominal": "prof. dr.",
          "initials": "A.",
          "first_name": "Andries",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Condensed Matter and Interfaces",
          "organisation_id": 80942,
          "ror": "https://ror.org/04pp8hn57",
          "active": false
        },
        {
          "role": "Researcher",
          "member_id": 160407,
          "last_name": "Linden",
          "initials": "D.P.C.J.",
          "first_name": "Dennis",
          "prefix": "van der ",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Soft Condensed Matter and Biophysics",
          "organisation_id": 81096,
          "ror": "https://ror.org/04pp8hn57",
          "active": false
        },
        {
          "role": "Researcher",
          "member_id": 207803,
          "last_name": "Evers",
          "initials": "W.H.",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Condensed Matter and Interfaces",
          "organisation_id": 80942,
          "ror": "https://ror.org/04pp8hn57",
          "active": false
        },
        {
          "role": "Co-applicant",
          "member_id": 115336,
          "last_name": "Mello Donegá",
          "degree_pre_nominal": "dr.",
          "initials": "C.",
          "first_name": "Celso",
          "prefix": "de",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Gecondenseerde Materie & Grensvlakken",
          "organisation_id": 80939,
          "ror": "https://ror.org/04pp8hn57",
          "active": true
        },
        {
          "role": "Main Applicant",
          "member_id": 177557,
          "last_name": "Meijerink",
          "degree_pre_nominal": "prof. dr.",
          "initials": "A.",
          "first_name": "Andries",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap",
          "organisation_id": 81461,
          "ror": "https://ror.org/04pp8hn57",
          "active": true
        },
        {
          "role": "Co-applicant",
          "member_id": 187210,
          "last_name": "Vanmaekelbergh",
          "degree_pre_nominal": "prof. dr.",
          "initials": "D.A.M.",
          "first_name": "Daniel",
          "prefix": "van",
          "organisation": "Universiteit Utrecht||Faculteit Bètawetenschappen||Departement Scheikunde||Debye Instituut voor Nanomaterialen Wetenschap||Condensed Matter and Interfaces",
          "organisation_id": 80942,
          "ror": "https://ror.org/04pp8hn57",
          "active": true
        }
      ]
    }
  ]
}